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Records |
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Author |
Li, Y.; Tan, H.; Lebedev, O.; Verbeeck, J.; Biermans, E.; Van Tendeloo, G.; Su, B.-L. |
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Title |
Insight into the growth of multiple branched MnOOH nanorods |
Type |
A1 Journal article |
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Year |
2010 |
Publication |
Crystal growth & design |
Abbreviated Journal |
Cryst Growth Des |
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Volume |
10 |
Issue |
7 |
Pages |
2969-2976 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Multiple branched manganese oxide hydroxide (MnOOH) nanorods prepared by a hydrothermal process were extensively studied by transmission electron microscopy (TEM). A model of the branch formation is proposed together with a study of the interface structure. The sword-like tip plays a crucial role for the nanorods to form different shapes. Importantly, the branching occurs at an angle of around either 57 degrees or 123 degrees. Specifically, a (111) twin plane can only be formed at the interface with a 123 degrees angle. The interfaces formed with a 57 degrees angle usually contain edge dislocations. Electron energy loss spectroscopy (EELS) demonstrates that the whole crystal has a uniform chemical composition. Interestingly, an epitaxial growth of Mn3O4 at the radial surface was also observed under electron beam irradiation; this is because of the rough purification of the products. The proposed mechanism is expected to shed light on the branched/dendrite nanostructure growth and to provide opportunities for further novel nanomaterial structure growth and design. |
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Corporate Author |
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Thesis |
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Place of Publication |
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Editor |
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Wos |
000279422700027 |
Publication Date |
2010-06-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1528-7483;1528-7505; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.055 |
Times cited |
41 |
Open Access |
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Notes |
Fwo; Esteem 026019 |
Approved |
Most recent IF: 4.055; 2010 IF: 4.390 |
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Call Number |
UA @ lucian @ c:irua:83886UA @ admin @ c:irua:83886 |
Serial |
1672 |
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Permanent link to this record |
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Author |
Morozov, V.A.; Lazoryak, B.I.; Shmurak, S.Z.; Kiselev, A.P.; Lebedev, O.I.; Gauquelin, N.; Verbeeck, J.; Hadermann, J.; Van Tendeloo, G. |
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Title |
Influence of the structure on the properties of NaxEuy(MoO4)z red phosphors |
Type |
A1 Journal article |
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Year |
2014 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
26 |
Issue |
10 |
Pages |
3238-3248 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Scheelite related compounds (A',A '')(n)[(B',B '')O-4](m) with B', B '' = W and/or Mo are promising new materials for red phosphors in pc-WLEDs (phosphor-converted white-light-emitting-diode) and solid-state lasers. Cation substitution in CaMoO4 of Ca2+ by the combination of Na+ and Eu3+, with the creation of A cation vacancies, has been investigated as a factor for controlling the scheelite-type structure and the luminescent properties. Na5Eu(MoO4)(4) and NaxEu(2-x)/33+square(2-x)/3MoO4 (0.138 <= x <= 0.5) phases with a scheelite-type structure were synthesized by the solid state method; their structural characteristics were investigated using transmission electron microscopy. Contrary to powder synchrotron X-ray diffraction before, the study by electron diffraction and high resolution transmission electron microscopy in this paper revealed that Na0.286Eu0.571MoO4 has a (3 + 2)D incommensurately modulated structure and that (3 + 2)D incommensurately modulated domains are present in Na0.200Eu0.600MoO4. It also confirmed the (3 + 1)D incommensurately modulated character of Na(0.138)Eu(0.621)Mo04. The luminescent properties of all phases under near-ultraviolet (n-UV) light have been investigated. The excitation spectra of these phosphors show the strongest absorption at about 395 nm, which matches well with the commercially available n-UV-emitting GaN-based LED chip. The emission spectra indicate an intense red emission due to the D-5(0) -> F-7(2) transition of Eu3+, with local minima in the intensity at Na0.286Eu0.571MoO4 and Na0.200Eu0.600MoO4 for similar to 613 nm and similar to 616 nm bands. The phosphor Na5Eu(MoO4)(4) shows the brightest red light emission among the phosphors in the Na2MoO4-Eu2/3MoO4 system and the maximum luminescence intensity of Na5Eu(MoO4)(4) (lambda(ex) = 395 nm) in the D-5(0) -> F-7(2) transition region is close to that of the commercially used red phosphor YVO4:Eu3+ (lambda(ex) = 326 nm). Electron energy loss spectroscopy measurements revealed the influence of the structure and Na/Eu cation distribution on the number and positions of bands in the UV-optical-infrared regions of the EELS spectrum. |
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Corporate Author |
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Thesis |
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Place of Publication |
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Language |
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Wos |
000336637000028 |
Publication Date |
2014-05-01 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
53 |
Open Access |
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Notes |
Fwo G039211n; Fwo G004413n; 278510 Vortex ECASJO_; |
Approved |
Most recent IF: 9.466; 2014 IF: 8.354 |
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Call Number |
UA @ lucian @ c:irua:117765UA @ admin @ c:irua:117765 |
Serial |
1652 |
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Permanent link to this record |
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Author |
Turner, S.; Lazar, S.; Freitag, B.; Egoavil, R.; Verbeeck, J.; Put, S.; Strauven, Y.; Van Tendeloo, G. |
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Title |
High resolution mapping of surface reduction in ceria nanoparticles |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Nanoscale |
Abbreviated Journal |
Nanoscale |
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Volume |
3 |
Issue |
8 |
Pages |
3385-3390 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Surface reduction of ceria nano octahedra with predominant {111} and {100} type surfaces is studied using a combination of aberration-corrected Transmission Electron Microscopy (TEM) and spatially resolved electron energy-loss spectroscopy (EELS) at high energy resolution and atomic spatial resolution. The valency of cerium ions at the surface of the nanoparticles is mapped using the fine structure of the Ce M4,5 edge as a fingerprint. The valency of the surface cerium ions is found to change from 4+ to 3+ owing to oxygen deficiency (vacancies) close to the surface. The thickness of this Ce3+ shell is measured using atomic-resolution Scanning Transmission Electron Microscopy (STEM)-EELS mapping over a {111} surface (the predominant facet for this ceria morphology), {111} type surface island steps and {100} terminating planes. For the {111} facets and for {111} surface islands, the reduction shell is found to extend over a single fully reduced surface plane and 12 underlying mixed valency planes. For the {100} facets the reduction shell extends over a larger area of 56 oxygen vacancy-rich planes. This finding provides a plausible explanation for the higher catalytic activity of the {100} surface facets in ceria. |
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Corporate Author |
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Publisher |
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Place of Publication |
Cambridge |
Editor |
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Language |
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Wos |
000293521700057 |
Publication Date |
2011-06-30 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2040-3364;2040-3372; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
7.367 |
Times cited |
127 |
Open Access |
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Notes |
Fwo |
Approved |
Most recent IF: 7.367; 2011 IF: 5.914 |
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Call Number |
UA @ lucian @ c:irua:90361UA @ admin @ c:irua:90361 |
Serial |
1458 |
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Permanent link to this record |
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Author |
Bals, S.; Batenburg, J.; Verbeeck, J.; Sijbers, J.; Van Tendeloo, G. |
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Title |
Quantitative three-dimensional reconstruction of catalyst particles for bamboo-like carbon nanotubes |
Type |
A1 Journal article |
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Year |
2007 |
Publication |
Nano letters |
Abbreviated Journal |
Nano Lett |
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Volume |
7 |
Issue |
12 |
Pages |
3669-3674 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
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Abstract |
The three-dimensional (3D) structure and chemical composition of bamboo-like carbon nanotubes including the catalyst particles that are. used during their growth are studied by discrete electron tomography in combination with energy-filtered transmission electron microscopy. It is found that cavities are present in the catalyst particles. Furthermore, only a small percentage of the catalyst particles consist of pure Cu, since a large volume fraction of the particles is oxidized to CU(2)0. These volume fractions are determined quantitatively from 3D reconstructions obtained by discrete tomography. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington |
Editor |
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Language |
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Wos |
000251581600022 |
Publication Date |
2007-11-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1530-6984;1530-6992; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
12.712 |
Times cited |
78 |
Open Access |
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Notes |
Fwo; Esteem |
Approved |
Most recent IF: 12.712; 2007 IF: 9.627 |
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Call Number |
UA @ lucian @ c:irua:66762UA @ admin @ c:irua:66762 |
Serial |
2768 |
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Permanent link to this record |
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Author |
Lebedev, O.I.; Verbeeck, J.; Van Tendeloo, G.; Hayashi, N.; Terashima, T.; Takano, M. |
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Title |
Structure and microstructure of epitaxial SrnFenO3n-1 films |
Type |
A1 Journal article |
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Year |
2004 |
Publication |
Philosophical magazine |
Abbreviated Journal |
Philos Mag |
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Volume |
84 |
Issue |
36 |
Pages |
3825-3841 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Thin films of SrFeO3-x (0 less than or equal to x less than or equal to 0.5) (SFO) grown on a (LaAlO3)(0.3) (SrAl0.5Ta0.5O3)(0.7) (LSAT) substrate by Pulsed laser deposition have been structurally investigated by electron diffraction and high resolution transmission electron microscopy for different post-deposition oxygen treatments. During the deposition and post-growth oxidation, the oxygen-reduced SFO films accept extra oxygen along the tetrahedral layers to minimize the elastic strain energy. The oxidation process stops at a concentration SFO2.875 and/or SFO2.75 because a zero misfit with the LSAT substrate is reached. A possible growth mechanism and phase transition mechanism are suggested. The non-oxidized films exhibit twin boundaries having a local perovskite-type structure with a nominal composition close to SFO3. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000225854700001 |
Publication Date |
2005-01-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1478-6435;1478-6443; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.505 |
Times cited |
4 |
Open Access |
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Notes |
reprint |
Approved |
Most recent IF: 1.505; 2004 IF: 1.167 |
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Call Number |
UA @ lucian @ c:irua:54755 |
Serial |
3287 |
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Permanent link to this record |
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Author |
Joy, R.M.; Pobedinskas, P.; Bourgeois, E.; Chakraborty, T.; Goerlitz, J.; Herrmann, D.; Noel, C.; Heupel, J.; Jannis, D.; Gauquelin, N.; D'Haen, J.; Verbeeck, J.; Popov, C.; Houssiau, L.; Becher, C.; Nesladek, M.; Haenen, K. |
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Title |
Photoluminescence of germanium-vacancy centers in nanocrystalline diamond films : implications for quantum sensing applications |
Type |
A1 Journal article |
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Year |
2024 |
Publication |
ACS applied nano materials |
Abbreviated Journal |
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Volume |
7 |
Issue |
4 |
Pages |
3873-3884 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Point defects in diamond, promising candidates for nanoscale pressure- and temperature-sensing applications, are potentially scalable in polycrystalline diamond fabricated using the microwave plasma-enhanced chemical vapor deposition (MW PE CVD) technique. However, this approach introduces residual stress in the diamond films, leading to variations in the characteristic zero phonon line (ZPL) of the point defect in diamond. Here, we report the effect of residual stress on germanium-vacancy (GeV) centers in MW PE CVD nanocrystalline diamond (NCD) films fabricated using single crystal Ge as the substrate and solid dopant source. GeV ensemble formation indicated by the zero phonon line (ZPL) at similar to 602 nm is confirmed by room temperature (RT) photoluminescence (PL) measurements. PL mapping results show spatial nonuniformity in GeV formation along with other defects, including silicon-vacancy centers in the diamond films. The residual stress in NCD results in shifts in the PL peak positions. By estimating a stress shift coefficient of (2.9 +/- 0.9) nm/GPa, the GeV PL peak position in the NCD film is determined to be between 598.7 and 603.2 nm. A larger ground state splitting due to the strain on a GeV-incorporated NCD pillar at a low temperature (10 K) is also reported. We also report the observation of intense ZPLs at RT that in some cases could be related to low Ge concentration and the surrounding crystalline environment. In addition, we also observe thicker microcrystalline diamond (MCD) films delaminate from the Ge substrate due to film residual stress and graphitic phase at the diamond/Ge substrate interface (confirmed by electron energy loss spectroscopy). Using this approach, a free-standing color center incorporated MCD film with dimensions up to 1 x 1 cm(2) is fabricated. Qualitative analysis using time-of-flight secondary ion mass spectroscopy reveals the presence of impurities, including Ge and silicon, in the MCD film. Our experimental results will provide insights into the scalability of GeV fabrication using the MW PE CVD technique and effectively implement NCD-based nanoscale-sensing applications. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
001164609600001 |
Publication Date |
2024-02-15 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2574-0970 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
5.9 |
Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: 5.9; 2024 IF: NA |
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Call Number |
UA @ admin @ c:irua:204826 |
Serial |
9164 |
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Permanent link to this record |
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Author |
Borgatti, F.; Park, C.; Herpers, A.; Offi, F.; Egoavil, R.; Yamashita, Y.; Yang, A.; Kobata, M.; Kobayashi, K.; Verbeeck, J.; Panaccione, G.; Dittmann, R.; |
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Title |
Chemical insight into electroforming of resistive switching manganite heterostructures |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Nanoscale |
Abbreviated Journal |
Nanoscale |
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Volume |
5 |
Issue |
9 |
Pages |
3954-3960 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
We have investigated the role of the electroforming process in the establishment of resistive switching behaviour for Pt/Ti/Pr0.5Ca0.5MnO3/SrRuO3 layered heterostructures (Pt/Ti/PCMO/SRO) acting as non-volatile Resistance Random Access Memories (RRAMs). Electron spectroscopy measurements demonstrate that the higher resistance state resulting from electroforming of as-prepared devices is strictly correlated with the oxidation of the top electrode Ti layer through field-induced electromigration of oxygen ions. Conversely, PCMO exhibits oxygen depletion and downward change of the chemical potential for both resistive states. Impedance spectroscopy analysis, supported by the detailed knowledge of these effects, provides an accurate model description of the device resistive behaviour. The main contributions to the change of resistance from the as-prepared (low resistance) to the electroformed (high resistance) states are respectively due to reduced PCMO at the boundary with the Ti electrode and to the formation of an anisotropic np junction between the Ti and the PCMO layers. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Cambridge |
Editor |
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Language |
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Wos |
000317859400051 |
Publication Date |
2013-03-05 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2040-3364;2040-3372; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
7.367 |
Times cited |
40 |
Open Access |
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Notes |
Vortex; Countatoms ECASJO_; |
Approved |
Most recent IF: 7.367; 2013 IF: 6.739 |
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Call Number |
UA @ lucian @ c:irua:108710UA @ admin @ c:irua:108710 |
Serial |
348 |
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Permanent link to this record |
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Author |
Krehl, J.; Guzzinati, G.; Schultz, J.; Potapov, P.; Pohl, D.; Martin, J.; Verbeeck, J.; Fery, A.; Büchner, B.; Lubk, A. |
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Title |
Spectral field mapping in plasmonic nanostructures with nanometer resolution |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Nature communications |
Abbreviated Journal |
Nat Commun |
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Volume |
9 |
Issue |
1 |
Pages |
4207 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Plasmonic nanostructures and -devices are rapidly transforming light manipulation technology by allowing to modify and enhance optical fields on sub-wavelength scales. Advances in this field rely heavily on the development of new characterization methods for the fundamental nanoscale interactions. However, the direct and quantitative mapping of transient electric and magnetic fields characterizing the plasmonic coupling has been proven elusive to date. Here we demonstrate how to directly measure the inelastic momentum transfer of surface plasmon modes via the energy-loss filtered deflection of a focused electron beam in a transmission electron microscope. By scanning the beam over the sample we obtain a spatially and spectrally resolved deflection map and we further show how this deflection is related quantitatively to the spectral component of the induced electric and magnetic fields pertaining to the mode. In some regards this technique is an extension to the established differential phase contrast into the dynamic regime. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000447074200005 |
Publication Date |
2018-10-11 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2041-1723 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
12.124 |
Times cited |
15 |
Open Access |
OpenAccess |
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Notes |
G.G. acknowledges support from a postdoctoral fellowship grant from the Fonds Wetenschappelijk Onderzoke-Vlaanderen (FWO). A.L. and J.K. have received funding from the European Research Council (ERC) under the Horizon 2020 research and innovation program of the European Union (grant agreement no. 715620). |
Approved |
Most recent IF: 12.124 |
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Call Number |
EMAT @ emat @c:irua:154355 |
Serial |
5058 |
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Permanent link to this record |
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Author |
Drijkoningen, S.; Pobedinskas, P.; Korneychuk, S.; Momot, A.; Balasubramaniam, Y.; Van Bael, M.K.; Turner, S.; Verbeeck, J.; Nesladekt, M.; Haenen, K. |
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Title |
On the Origin of Diamond Plates Deposited at Low Temperature |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Crystal growth & design |
Abbreviated Journal |
Cryst Growth Des |
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Volume |
17 |
Issue |
8 |
Pages |
4306-4314 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The crucial requirement for diamond growth at low temperatures, enabling a wide range of new applications, is a high plasma density at a low gas pressure, which leads to a low thermal load onto sensitive substrate materials. While these conditions are not within reach for resonance cavity plasma systems, linear antenna microwave delivery systems allow the deposition of high quality diamond films at temperatures around 400 degrees C and at pressures below 1 mbar. In this work the codeposition of high quality plates and octahedral diamond grains in nanocrystalline films is reported. In contrast to previous reports claiming the need for high temperatures (T >= 850 degrees C), low temperatures (320 degrees C <= T <= 410 degrees C) were sufficient to deposit diamond plate structures. Cross-sectional high resolution transmission electron microscopy studies show that these plates are faulty cubic diamond terminated by large {111} surface facets with very little sp(2) bonded carbon in the grain boundaries. Raman and electron energy loss spectroscopy studies confirm a high diamond quality, above 93% sp(3) carbon content. Three potential mechanisms, that can account for the initial development of the observed plates rich with stacking faults, and are based on the presence of impurities, are proposed. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000407089600031 |
Publication Date |
2017-06-30 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1528-7483 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.055 |
Times cited |
23 |
Open Access |
Not_Open_Access |
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Notes |
; The Research Foundation – Flanders (FWO) is gratefully acknowledged for financial support in the form of the Postdoctoral Fellowships of P.P. and S.T., contract G.0044.13N “Charge ordering” (S.K., J.V.), the Methusalem “Nano” network, and the Hercules-linear antenna and Raman equipment. ; |
Approved |
Most recent IF: 4.055 |
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Call Number |
UA @ lucian @ c:irua:145735UA @ admin @ c:irua:145735 |
Serial |
4746 |
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Permanent link to this record |
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Author |
Spreitzer, M.; Egoavil, R.; Verbeeck, J.; Blank, D.H.A.; Rijnders, G. |
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Title |
Pulsed laser deposition of SrTiO3 on a H-terminated Si substrate |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Journal of materials chemistry C : materials for optical and electronic devices |
Abbreviated Journal |
J Mater Chem C |
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Volume |
1 |
Issue |
34 |
Pages |
5216-5222 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Interfacing oxides with silicon is a long-standing problem related to the integration of multifunctional oxides with semiconductor devices and the replacement of SiO2 with high-k gate oxides. In our study, pulsed laser deposition was used to prepare a SrTiO3 (STO) thin film on a H-terminated Si substrate. The main purpose of our work was to verify the ability of H-termination against the oxidation of Si during the PLD process and to analyze the resulting interfaces. In the first part of the study, the STO was deposited directly on the Si, leading to the formation of a preferentially textured STO film with a (100) orientation. In the second part, SrO was used as a buffer layer, which enabled the partial epitaxial growth of STO with STO(110)parallel to Si(100) and STO[001]parallel to Si[001]. The change in the growth direction induced by the application of a SrO buffer was governed by the formation of a SrO(111) intermediate layer and subsequently by the minimization of the lattice misfit between the STO and the SrO. Under the investigated conditions, approximately 10 nm thick interfacial layers formed between the STO and the Si due to reactions between the deposited material and the underlying H-terminated Si. In the case of direct STO deposition, SiOx formed at the interface with the silicon, while in the case when SrO was used as a buffer, strontium silicate grew directly on the silicon, which improves the growth quality of the uppermost STO. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000322911900005 |
Publication Date |
2013-07-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
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|
ISSN |
2050-7526;2050-7534; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
5.256 |
Times cited |
23 |
Open Access |
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|
Notes |
Ifox; Esteem2; Vortex; Countatoms; esteem2jra3 ECASJO; |
Approved |
Most recent IF: 5.256; 2013 IF: NA |
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Call Number |
UA @ lucian @ c:irua:110798UA @ admin @ c:irua:110798 |
Serial |
2739 |
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Permanent link to this record |
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Author |
Huijben, M.; Koster, G.; Kruize, M.K.; Wenderich, S.; Verbeeck, J.; Bals, S.; Slooten, E.; Shi, B.; Molegraaf, H.J.A.; Kleibeuker, J.E.; Van Aert, S.; Goedkoop, J.B.; Brinkman, A.; Blank, D.H.A.; Golden, M.S.; Van Tendeloo, G.; Hilgenkamp, H.; Rijnders, G.; |
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Title |
Defect engineering in oxide heterostructures by enhanced oxygen surface exchange |
Type |
A1 Journal article |
|
Year |
2013 |
Publication |
Advanced functional materials |
Abbreviated Journal |
Adv Funct Mater |
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Volume |
23 |
Issue |
42 |
Pages |
5240-5248 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
The synthesis of materials with well-controlled composition and structure improves our understanding of their intrinsic electrical transport properties. Recent developments in atomically controlled growth have been shown to be crucial in enabling the study of new physical phenomena in epitaxial oxide heterostructures. Nevertheless, these phenomena can be influenced by the presence of defects that act as extrinsic sources of both doping and impurity scattering. Control over the nature and density of such defects is therefore necessary to fully understand the intrinsic materials properties and exploit them in future device technologies. Here, it is shown that incorporation of a strontium copper oxide nano-layer strongly reduces the impurity scattering at conducting interfaces in oxide LaAlO3SrTiO3(001) heterostructures, opening the door to high carrier mobility materials. It is proposed that this remote cuprate layer facilitates enhanced suppression of oxygen defects by reducing the kinetic barrier for oxygen exchange in the hetero-interfacial film system. This design concept of controlled defect engineering can be of significant importance in applications in which enhanced oxygen surface exchange plays a crucial role. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Weinheim |
Editor |
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Language |
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Wos |
000327480900003 |
Publication Date |
2013-06-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1616-301X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
12.124 |
Times cited |
87 |
Open Access |
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Notes |
Countatoms; Vortex; Fwo; Ifox ECASJO_; |
Approved |
Most recent IF: 12.124; 2013 IF: 10.439 |
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Call Number |
UA @ lucian @ c:irua:109273UA @ admin @ c:irua:109273 |
Serial |
615 |
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Permanent link to this record |
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Author |
Burriel, M.; Casa-Cabanas, M.; Zapata, J.; Tan, H.; Verbeeck, J.; Solis, C.; Roqueta, J.; Skinner, S.J.; Kilner, J.A.; Van Tendeloo, G.; Santiso, J. |
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Title |
Influence of the microstructure on the high-temperature transport properties of GdBaCo2O5.5+\delta epitaxial films |
Type |
A1 Journal article |
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Year |
2010 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
22 |
Issue |
19 |
Pages |
5512-5520 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Epitaxial thin films of GdBaCo2O5.5+δ (GBCO) grown by pulsed laser deposition have been studied as a function of deposition conditions. The variation in film structure, domain orientation, and microstructure upon deviations in the cation composition have been correlated with the charge transport properties of the films. The epitaxial GBCO films mainly consist of single- and double-perovskite regions that are oriented in different directions depending on the deposition temperature. Additionally, cobalt depletion induces the formation of a high density of stacking defects in the films, consisting of supplementary GdO planes along the c-axis of the material. The presence of such defects progressively reduces the electrical conductivity. The films closer to the stoichiometric composition have shown p-type electronic conductivity at high pO2 with values as high as 800 S/cm at 330 °C in 1 atm O2, and with a pO2 power dependence with an exponent as low as 1/25, consistent with the behavior reported for bulk GBCO. These values place GBCO thin films as a very promising material to be applied as cathodes in intermediate temperature solid oxide fuel cells. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000282471000013 |
Publication Date |
2010-09-20 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
|
Edition |
|
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ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
17 |
Open Access |
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|
Notes |
Fwo; Esteem 026019 |
Approved |
Most recent IF: 9.466; 2010 IF: 6.400 |
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Call Number |
UA @ lucian @ c:irua:85412UA @ admin @ c:irua:85412 |
Serial |
1648 |
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Permanent link to this record |
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Author |
Morozov, V.A.; Arakcheeva, A.V.; Pattison, P.; Meert, K.W.; Smet, P.F.; Poelman, D.; Gauquelin, N.; Verbeeck, J.; Abakumov, A.M.; Hadermann, J. |
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Title |
KEu(MoO4)2 : polymorphism, structures, and luminescent properties |
Type |
A1 Journal article |
|
Year |
2015 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
27 |
Issue |
27 |
Pages |
5519-5530 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
In this paper, with the example of two different polymorphs of KEu(MoO4)2, the influence of the ordering of the A-cations on the luminescent properties in scheelite related compounds (A′,A″)n[(B′,B″)O4]m is investigated. The polymorphs were synthesized using a solid state method. The study confirmed the existence of only two polymorphic forms at annealing temperature range 9231203 K and ambient pressure: a low temperature anorthic α-phase and a monoclinic high temperature β-phase with an incommensurately modulated structure. The structures of both polymorphs were solved using transmission electron microscopy and refined from synchrotron powder X-ray diffraction data. The monoclinic β-KEu(MoO4)2 has a (3+1)-dimensional incommensurately modulated structure (superspace group I2/b(αβ0)00, a = 5.52645(4) Å, b = 5.28277(4) Å, c = 11.73797(8) Å, γ = 91.2189(4)o, q = 0.56821(2)a*0.12388(3)b*), whereas the anorthic α-phase is (3+1)-dimensional commensurately modulated (superspace group I1̅(αβγ)0, a = 5.58727(22) Å, b = 5.29188(18)Å, c = 11.7120(4) Å, α = 90.485(3)o, β = 88.074(3)o, γ = 91.0270(23)o, q = 1/2a* + 1/2c*). In both cases the modulation arises due to Eu/K cation ordering at the A site: the formation of a 2-dimensional Eu3+ network is characteristic for the α-phase, while a 3-dimensional Eu3+-framework is observed for the β-phase structure. The luminescent properties of KEu(MoO4)2 samples prepared under different annealing conditions were measured, and the relation between their optical properties and their structures is discussed. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000360323700011 |
Publication Date |
2015-07-29 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
26 |
Open Access |
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|
Notes |
278510 Vortex; Fwo G039211n; G004413n ECASJO_; |
Approved |
Most recent IF: 9.466; 2015 IF: 8.354 |
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Call Number |
c:irua:127244 |
Serial |
3537 |
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Permanent link to this record |
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Author |
Mueller, K.; Krause, F.F.; Béché, A.; Schowalter, M.; Galioit, V.; Loeffler, S.; Verbeeck, J.; Zweck, J.; Schattschneider, P.; Rosenauer, A. |
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Title |
Atomic electric fields revealed by a quantum mechanical approach to electron picodiffraction |
Type |
A1 Journal article |
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Year |
2014 |
Publication |
Nature communications |
Abbreviated Journal |
Nat Commun |
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Volume |
5 |
Issue |
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Pages |
5653 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
By focusing electrons on probes with a diameter of 50 pm, aberration-corrected scanning transmission electron microscopy (STEM) is currently crossing the border to probing subatomic details. A major challenge is the measurement of atomic electric fields using differential phase contrast (DPC) microscopy, traditionally exploiting the concept of a field- induced shift of diffraction patterns. Here we present a simplified quantum theoretical interpretation of DPC. This enables us to calculate the momentum transferred to the STEM probe from diffracted intensities recorded on a pixel array instead of conventional segmented bright- field detectors. The methodical development yielding atomic electric field, charge and electron density is performed using simulations for binary GaN as an ideal model system. We then present a detailed experimental study of SrTiO3 yielding atomic electric fields, validated by comprehensive simulations. With this interpretation and upgraded instrumentation, STEM is capable of quantifying atomic electric fields and high-contrast imaging of light atoms. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000347227700003 |
Publication Date |
2014-12-15 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2041-1723; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
12.124 |
Times cited |
197 |
Open Access |
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Notes |
246791 COUNTATOMS; 278510 VORTEX; Hercules; 312483 ESTEEM2; esteem2ta; ECASJO; |
Approved |
Most recent IF: 12.124; 2014 IF: 11.470 |
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Call Number |
UA @ lucian @ c:irua:122835UA @ admin @ c:irua:122835 |
Serial |
166 |
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Permanent link to this record |
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Author |
Van Tendeloo, G.; Bals, S.; Van Aert, S.; Verbeeck, J.; van Dyck, D. |
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Title |
Advanced electron microscopy for advanced materials |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Advanced materials |
Abbreviated Journal |
Adv Mater |
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Volume |
24 |
Issue |
42 |
Pages |
5655-5675 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Vision lab |
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Abstract |
The idea of this Review is to introduce newly developed possibilities of advanced electron microscopy to the materials science community. Over the last decade, electron microscopy has evolved into a full analytical tool, able to provide atomic scale information on the position, nature, and even the valency atoms. This information is classically obtained in two dimensions (2D), but can now also be obtained in 3D. We show examples of applications in the field of nanoparticles and interfaces. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Weinheim |
Editor |
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Language |
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Wos |
000310602200001 |
Publication Date |
2012-08-21 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0935-9648; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
19.791 |
Times cited |
107 |
Open Access |
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Notes |
This work was supported by funding from the European Research Council under the 7th Framework Program (FP7), ERC grant No 246791 – COUNTATOMS. J.V. Acknowledges funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant 278510 VORTEX. The authors gratefully acknowledge funding from the Research Foundation Flanders (FWO, Belgium). The Qu-Ant-EM microscope was partly funded by the Hercules Fund from the Flemish Government. We thank Rafal Dunin-Borkowski for providing Figure 5d. The authors would like to thank the colleagues who have contributed to this work over the years, including K.J. Batenburg, R. Erni, B. Goris, F. Leroux, H. Lichte, A. Lubk, B. Partoens, M. D. Rossell, P. Schattschneider, B. Schoeters, D. Schryvers, H. Tan, H. Tian, S. Turner, M. van Huis. ECASJO_; |
Approved |
Most recent IF: 19.791; 2012 IF: 14.829 |
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Call Number |
UA @ lucian @ c:irua:100470UA @ admin @ c:irua:100470 |
Serial |
70 |
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Permanent link to this record |
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Author |
Heyer, S.; Janssen, W.; Turner, S.; Lu, Y.-G.; Yeap, W.S.; Verbeeck, J.; Haenen, K.; Krueger, A. |
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Title |
Toward deep blue nano hope diamonds : heavily boron-doped diamond nanoparticles |
Type |
A1 Journal article |
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Year |
2014 |
Publication |
ACS nano |
Abbreviated Journal |
Acs Nano |
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Volume |
8 |
Issue |
6 |
Pages |
5757-5764 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
The production of boron-doped diamond nanoparticles enables the application of this material for a broad range of fields, such as electrochemistry, thermal management, and fundamental superconductivity research. Here we present the production of highly boron-doped diamond nanoparticles using boron-doped CVD diamond films as a starting material. In a multistep milling process followed by purification and surface oxidation we obtained diamond nanoparticles of 1060 nm with a boron content of approximately 2.3 × 1021 cm3. Aberration-corrected HRTEM reveals the presence of defects within individual diamond grains, as well as a very thin nondiamond carbon layer at the particle surface. The boron K-edge electron energy-loss near-edge fine structure demonstrates that the B atoms are tetrahedrally embedded into the diamond lattice. The boron-doped diamond nanoparticles have been used to nucleate growth of a boron-doped diamond film by CVD that does not contain an insulating seeding layer. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000338089200039 |
Publication Date |
2014-04-09 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1936-0851;1936-086X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
13.942 |
Times cited |
71 |
Open Access |
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Notes |
the Research Foundation Flanders (FWO-Vlaanderen) (G.0555.10N;G.0568.10N; G.0456.12; G0044.13N and a postdoctoral scholarship for S.T.); EU FP7 through Marie Curie ITN “MATCON” (PITNGA-127 2009-238201)the Collaborative Project “DINAMO” (No. 245122) Integrated Infrastructure Initiative, Reference No. 312483-ESTEEM2.; esteem2_jra3 |
Approved |
Most recent IF: 13.942; 2014 IF: 12.881 |
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Call Number |
UA @ lucian @ c:irua:117599 |
Serial |
3683 |
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Permanent link to this record |
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Author |
Turner, S.; Lu, Y.-G.; Janssens, S.D.; da Pieve, F.; Lamoen, D.; Verbeeck, J.; Haenen, K.; Wagner, P.; Van Tendeloo, G. |
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Title |
Local boron environment in B-doped nanocrystalline diamond films |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Nanoscale |
Abbreviated Journal |
Nanoscale |
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Volume |
4 |
Issue |
19 |
Pages |
5960-5964 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Thin films of heavily B-doped nanocrystalline diamond (B:NCD) have been investigated by a combination of high resolution annular dark field scanning transmission electron microscopy and spatially resolved electron energy-loss spectroscopy performed on a state-of-the-art aberration corrected instrument to determine the B concentration, distribution and the local B environment. Concentrations of [similar]1 to 3 at.% of boron are found to be embedded within individual grains. Even though most NCD grains are surrounded by a thin amorphous shell, elemental mapping of the B and C signal shows no preferential embedding of B in these amorphous shells or in grain boundaries between the NCD grains, in contrast with earlier work on more macroscopic superconducting polycrystalline B-doped diamond films. Detailed inspection of the fine structure of the boron K-edge and comparison with density functional theory calculated fine structure energy-loss near-edge structure signatures confirms that the B atoms present in the diamond grains are substitutional atoms embedded tetrahedrally into the diamond lattice. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Cambridge |
Editor |
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Language |
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Wos |
000308705900026 |
Publication Date |
2012-08-09 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
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ISSN |
2040-3364;2040-3372; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
7.367 |
Times cited |
39 |
Open Access |
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|
Notes |
FWO G056810N; GOA XANES meets ELNES; 246791 COUNTATOMS; Hercules; 262348 ESMI; Methusalem Nano |
Approved |
Most recent IF: 7.367; 2012 IF: 6.233 |
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Call Number |
UA @ lucian @ c:irua:101227UA @ admin @ c:irua:101227 |
Serial |
1825 |
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Permanent link to this record |
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Author |
Birkholzer, Y.A.; Sotthewes, K.; Gauquelin, N.; Riekehr, L.; Jannis, D.; van der Minne, E.; Bu, Y.; Verbeeck, J.; Zandvliet, H.J.W.; Koster, G.; Rijnders, G. |
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Title |
High-strain-induced local modification of the electronic properties of VO₂ thin films |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
ACS applied electronic materials |
Abbreviated Journal |
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Volume |
4 |
Issue |
12 |
Pages |
6020-6028 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Vanadium dioxide (VO2) is a popular candidate for electronic and optical switching applications due to its well-known semiconductor-metal transition. Its study is notoriously challenging due to the interplay of long- and short-range elastic distortions, as well as the symmetry change and the electronic structure changes. The inherent coupling of lattice and electronic degrees of freedom opens the avenue toward mechanical actuation of single domains. In this work, we show that we can manipulate and monitor the reversible semiconductor-to-metal transition of VO2 while applying a controlled amount of mechanical pressure by a nanosized metallic probe using an atomic force microscope. At a critical pressure, we can reversibly actuate the phase transition with a large modulation of the conductivity. Direct tunneling through the VO2-metal contact is observed as the main charge carrier injection mechanism before and after the phase transition of VO2. The tunneling barrier is formed by a very thin but persistently insulating surface layer of the VO2. The necessary pressure to induce the transition decreases with temperature. In addition, we measured the phase coexistence line in a hitherto unexplored regime. Our study provides valuable information on pressure-induced electronic modifications of the VO2 properties, as well as on nanoscale metal-oxide contacts, which can help in the future design of oxide electronics. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000890974900001 |
Publication Date |
2022-11-18 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2637-6113 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
|
Times cited |
2 |
Open Access |
OpenAccess |
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Notes |
This work received financial support from the project Green ICT (grant number 400.17.607) of the research program NWA, which is financed by the Dutch Research Council (NWO), Research Foundation Flanders (FWO grant number G0F1320N), and the European Union’s Horizon 2020 research and innovation program within a contract for Integrating Activities for Advanced Communities (grant number 823717 − ESTEEM3). The K2 camera was funded through the Research Foundation Flanders (FWO-Hercules grant number G0H4316N – “Direct electron detector for soft matter TEM”).; esteem3reported; esteem3jra |
Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:192712 |
Serial |
7309 |
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Permanent link to this record |
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Author |
Achari, A.; Bekaert, J.; Sreepal, V.; Orekhov, A.; Kumaravadivel, P.; Kim, M.; Gauquelin, N.; Pillai, P.B.; Verbeeck, J.; Peeters, F.M.; Geim, A.K.; Milošević, M.V.; Nair, R.R. |
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Title |
Alternating superconducting and charge density wave monolayers within bulk 6R-TaS₂ |
Type |
A1 Journal article |
|
Year |
2022 |
Publication |
Nano letters |
Abbreviated Journal |
Nano Lett |
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Volume |
22 |
Issue |
15 |
Pages |
6268-6275 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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Abstract |
Van der Waals (vdW) heterostructures continue to attract intense interest as a route of designing materials with novel properties that cannot be found in nature. Unfortunately, this approach is currently limited to only a few layers that can be stacked on top of each other. Here, we report a bulk vdW material consisting of superconducting 1H TaS2 monolayers interlayered with 1T TaS2 monolayers displaying charge density waves (CDW). This bulk vdW heterostructure is created by phase transition of 1T-TaS2 to 6R at 800 degrees C in an inert atmosphere. Its superconducting transition (T-c) is found at 2.6 K, exceeding the T-c of the bulk 2H phase. Using first-principles calculations, we argue that the coexistence of superconductivity and CDW within 6R-TaS2 stems from amalgamation of the properties of adjacent 1H and 1T monolayers, where the former dominates the superconducting state and the latter the CDW behavior. |
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Corporate Author |
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Thesis |
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Place of Publication |
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Language |
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Wos |
000831832100001 |
Publication Date |
2022-07-20 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
|
|
ISSN |
1530-6984 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
10.8 |
Times cited |
12 |
Open Access |
OpenAccess |
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Notes |
This work was supported by the Royal Society, the Leverhulme Trust (PLP-2018-220), the Engineering and Physical Sciences Research Council (EP/N005082/1), and European Research Council (contract 679689). The authors acknowledge the use of the facilities at the Henry Royce Institute and associated support services. J.B. is a postdoctoral fellow of Research Foundation-Flanders (FWO-Vlaanderen). Computational resources were provided by the VSC (Flemish Supercomputer Center), funded by the FWO and the Flemish Governmentdepartment EWI. This work was also performed under a transnational access provision funded by the European Union under the Horizon 2020 programme within a contract for Integrating Activities for Advanced Communities No 823717 − ESTEEM3; esteem3reported; esteem3jra |
Approved |
Most recent IF: 10.8 |
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Call Number |
UA @ admin @ c:irua:189495 |
Serial |
7077 |
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Permanent link to this record |
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Author |
Liao, Z; , Green, R.J; Gauquelin, N; Macke, S.; Li, L.; Gonnissen, J; Sutarto, R.; Houwman, E.P.; Zhong, Z.; Van Aert, S.; Verbeeck, J.; Sawatzky, G.A.; Huijben, M.; Koster, G.; Rijnders, G. |
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Title |
Long-Range Domain Structure and Symmetry Engineering by Interfacial Oxygen Octahedral Coupling at Heterostructure Interface |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Advanced functional materials |
Abbreviated Journal |
Adv Funct Mater |
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Volume |
26 |
Issue |
26 |
Pages |
6627-6634 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
In epitaxial thin film systems, the crystal structure and its symmetry deviate from the bulk counterpart due to various mechanisms such as epitaxial strain and interfacial structural coupling, which is accompanyed by a change in their properties. In perovskite materials, the crystal symmetry can be described by rotations of sixfold coordinated transition metal oxygen octahedra, which are found to be altered at interfaces. Here, it is unraveled how the local oxygen octahedral coupling at perovskite heterostructural interfaces strongly influences the domain structure and symmetry of the epitaxial films resulting in design rules to induce various structures in thin films using carefully selected combinations of substrate/buffer/film. Very interestingly it is discovered that these combinations lead to structure changes throughout the full thickness of the film. The results provide a deep insight into understanding the origin of induced structures in a perovskite heterostructure and an intelligent route to achieve unique functional properties. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000384809800010 |
Publication Date |
2016-06-23 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1616-301x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
12.124 |
Times cited |
23 |
Open Access |
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Notes |
We thank B. Keimer for valuable discussions. M.H., G.K. and G.R. acknowledge funding from DESCO program of the Dutch Foundation for Fundamental Research on Matter (FOM) with financial support from the Netherlands Organization for Scientific Research (NWO). This work was funded by the European Union Council under the 7th Framework Program (FP7) grant nr NMP3-LA-2010-246102 IFOX. J.V. and S.V.A. acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0044.13N, G.0374.13N, G.0368.15N, G.0369.15N). The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government. N.G. acknowledges funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant 278510 VORTEX. N.G., J.G., S.V.A., J.V. acknowledge financial support from the European Union under the Seventh Framework Program under a contract for an Integrated Infrastructure Initiative (Reference No. 312483-ESTEEM2). The Canadian work was supported by NSERC and the Max Planck-UBC Centre for Quantum Materials. Some experiments for this work were performed at the Canadian Light Source, which is funded by the Canada Foundation for Innovation, NSERC, the National Research Council of Canada, the Canadian Institutes of Health Research, the Government of Saskatchewan, Western Economic Diversification Canada, and the University of Saskatchewan.; esteem2jra2; esteem2jra3; ECASJO_; |
Approved |
Most recent IF: 12.124 |
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Call Number |
EMAT @ emat @ c:irua:144663UA @ admin @ c:irua:144663 |
Serial |
4106 |
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Permanent link to this record |
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Author |
Morozov, V.A.; Raskina, M.V.; Lazoryak, B.I.; Meert, K.W.; Korthout, K.; Smet, P.F.; Poelman, D.; Gauquelin, N.; Verbeeck, J.; Abakumov, A.M.; Hadermann, J.; |
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Title |
Crystal Structure and Luminescent Properties of R2-xEux(MoO4)(3) (R = Gd, Sm) Red Phosphors |
Type |
A1 Journal article |
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Year |
2014 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
26 |
Issue |
24 |
Pages |
7124-7136 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The R-2(MoO4)(3) (R = rare earth elements) molybdates doped with Eu3+ cations are interesting red-emitting materials for display and solid-state lighting applications. The structure and luminescent properties of the R2-xEux(MoO4)(3) (R = Gd, Sm) solid solutions have been investigated as a function of chemical composition and preparation conditions. Monoclinic (alpha) and orthorhombic (beta') R2-xEux(MoO4)(3) (R = Gd, Sm; 0 <= x <= 2) modifications were prepared by solid-state reaction, and their structures were investigated using synchrotron powder X-ray diffraction and transmission electron microscopy. The pure orthorhombic beta'-phases could be synthesized only by quenching from high temperature to room temperature for Gd2-xEux(MoO4)(3) in the Eu3+-rich part (x > 1) and for all Sm2-xEux(MoO4)(3) solid solutions. The transformation from the alpha-phase to the beta'-phase results in a notable increase (similar to 24%) of the unit cell volume for all R2-xEux(MoO4)(3) (R = Sm, Gd) solid solutions. The luminescent properties of all R2-xEux(MoO4)(3) (R = Gd, Sm; 0 <= x <= 2) solid solutions were measured, and their optical properties were related to their structural properties. All R2-xEux(MoO4)(3) (R = Gd, Sm; 0 <= x <= 2) phosphors emit intense red light dominated by the D-5(0)-> F-7(2) transition at similar to 616 nm. However, a change in the multiplet splitting is observed when switching from the monoclinic to the orthorhombic structure, as a consequence of the change in coordination polyhedron of the luminescent ion from RO8 to RO7 for the alpha- and beta'-modification, respectively. The Gd2-xEux(MoO4)(3) solid solutions are the most efficient emitters in the range of 0 < x < 1.5, but their emission intensity is comparable to or even significantly lower than that of Sm2-xEux(MoO4)(3) for higher Eu3+ concentrations (1.5 <= x <= 1.75). Electron energy loss spectroscopy (EELS) measurements revealed the influence of the structure and element content on the number and positions of bands in the ultraviolet-visible-infrared regions of the EELS spectrum. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000347139700027 |
Publication Date |
2014-11-27 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
24 |
Open Access |
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Notes |
Fwo G039211n; G004413n; 278510 Vortex ECASJO_; |
Approved |
Most recent IF: 9.466; 2014 IF: 8.354 |
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Call Number |
UA @ lucian @ c:irua:122829UA @ admin @ c:irua:122829 |
Serial |
558 |
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Permanent link to this record |
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Author |
Do, M.T.; Gauquelin, N.; Nguyen, M.D.; Wang, J.; Verbeeck, J.; Blom, F.; Koster, G.; Houwman, E.P.; Rijnders, G. |
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Title |
Interfacial dielectric layer as an origin of polarization fatigue in ferroelectric capacitors |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Scientific Reports |
Abbreviated Journal |
Sci Rep-Uk |
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Volume |
10 |
Issue |
1 |
Pages |
7310 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Origins of polarization fatigue in ferroelectric capacitors under electric field cycling still remain unclear. Here, we experimentally identify origins of polarization fatigue in ferroelectric PbZr0.52Ti0.48O3 (PZT) thin-film capacitors by investigating their fatigue behaviours and interface structures. The PZT layers are epitaxially grown on SrRuO3-buffered SrTiO3 substrates by a pulsed laser deposition (PLD), and the capacitor top-electrodes are various, including SrRuO3 (SRO) made by in-situ PLD, Pt by in-situ PLD (Pt-inPLD) and ex-situ sputtering (Pt-sputtered). We found that fatigue behaviour of the capacitor is directly related to the top-electrode/PZT interface structure. The Pt-sputtered/PZT/SRO capacitor has a thin defective layer at the top interface and shows early fatigue while the Pt-inPLD/PZT/SRO and SRO/PZT/SRO capacitor have clean top-interfaces and show much more fatigue resistance. The defective dielectric layer at the Pt-sputtered/PZT interface mainly contains carbon contaminants, which form during the capacitor ex-situ fabrication. Removal of this dielectric layer significantly delays the fatigue onset. Our results clearly indicate that dielectric layer at ferroelectric capacitor interfaces is the main origin of polarization fatigue, as previously proposed in the charge injection model. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000559953800003 |
Publication Date |
2020-04-30 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2045-2322 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.6 |
Times cited |
18 |
Open Access |
OpenAccess |
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Notes |
; The authors acknowledge the financial support of the Nederlandse Organisatie voor Wetenschappelijk Onderzoek through Grant No. F62.3.15559. ; |
Approved |
Most recent IF: 4.6; 2020 IF: 4.259 |
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Call Number |
EMAT @ emat @c:irua:169865 |
Serial |
6374 |
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Permanent link to this record |
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Author |
Lebedev, O.I.; Verbeeck, J.; Van Tendeloo, G.; Dubourdieu, C.; Rosina, M.; Chaudouët, P. |
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Title |
Structure and properties of artificial [(La0.7Sr0.3MnO3)m(SrTiO3)n]15 superlattices on (001)SrTiO3 |
Type |
A1 Journal article |
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Year |
2003 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
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Volume |
94 |
Issue |
12 |
Pages |
7646-7656 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Complex [(La0.7Sr0.3MnO3)(m)(SrTiO3)(n)] [(LSMO)(m)/(STO)(8)](15) superlattices with different layer thicknesses (m=5, 8, 12, 16, 32) have been prepared using pulsed liquid injection metalorganic chemical vapor deposition. Transmission electron microscopy and electron diffraction reveal a very clear and well-separated layer sequence. The remarkable microstructure, as well as the ferromagnetic transition temperature, depends on the LSMO layer thickness. Apart from a very clear layer sequence, electron microscopy shows evidence of a self-assembled nanostructure formation: SrMnO3 nanoinclusions and associated SrTiO3-SrMnO3 thin walls. A formation model and growth mechanism for the self-assembled structure is proposed, based on high resolution and energy filtered elemental imaging. (C) 2003 American Institute of Physics. |
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Corporate Author |
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Thesis |
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Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000186969900042 |
Publication Date |
2003-12-04 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0021-8979; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.068 |
Times cited |
22 |
Open Access |
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Notes |
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Approved |
Most recent IF: 2.068; 2003 IF: 2.171 |
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Call Number |
UA @ lucian @ c:irua:54822 |
Serial |
3292 |
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Permanent link to this record |
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Author |
Palgrave, R.G.; Borisov, P.; Dyer, M.S.; McMitchell, S.R.C.; Darling, G.R.; Claridge, J.B.; Batuk, M.; Tan, H.; Tian, H.; Verbeeck, J.; Hadermann, J.; Rosseinsky, M.J.; |
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Title |
Artificial construction of the layered Ruddlesden-Popper manganite La2Sr2Mn3O10 by reflection high energy electron diffraction monitored pulsed laser deposition |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Journal of the American Chemical Society |
Abbreviated Journal |
J Am Chem Soc |
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Volume |
134 |
Issue |
18 |
Pages |
7700-7714 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Pulsed laser deposition has been used to artificially construct the n = 3 Ruddlesden Popper structure La2Sr2Mn3O10 in epitaxial thin film form by sequentially layering La1-xSrxMnO3 and SrO unit cells aided by in situ reflection high energy electron diffraction monitoring. The interval deposition technique was used to promote two-dimensional SrO growth. X-ray diffraction and cross-sectional transmission electron microscopy indicated that the trilayer structure had been formed. A site ordering was found to differ from that expected thermodynamically, with the smaller Sr2+ predominantly on the R site due to kinetic trapping of the deposited cation sequence. A dependence of the out-of-plane lattice parameter on growth pressure was interpreted as changing the oxygen content of the films. Magnetic and transport measurements on fully oxygenated films indicated a frustrated magnetic ground state characterized as a spin glass-like magnetic phase with the glass temperature T-g approximate to 34 K. The magnetic frustration has a clear in-plane (ab) magnetic anisotropy, which is maintained up to temperatures of 150 K. Density functional theory calculations suggest competing antiferromagnetic and ferromagnetic long-range orders, which are proposed as the origin of the low-temperature glassy state. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000303696200029 |
Publication Date |
2012-03-30 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0002-7863;1520-5126; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
13.858 |
Times cited |
27 |
Open Access |
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Notes |
Fwo; Esteem 026019 |
Approved |
Most recent IF: 13.858; 2012 IF: 10.677 |
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Call Number |
UA @ lucian @ c:irua:98947UA @ admin @ c:irua:98947 |
Serial |
153 |
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Permanent link to this record |
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Author |
Gauquelin, N.; Forte, F.; Jannis, D.; Fittipaldi, R.; Autieri, C.; Cuono, G.; Granata, V.; Lettieri, M.; Noce, C.; Miletto-Granozio, F.; Vecchione, A.; Verbeeck, J.; Cuoco, M. |
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Title |
Pattern Formation by Electric-Field Quench in a Mott Crystal |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Nano letters |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
The control of Mott phase is intertwined with the spatial reorganization of the electronic states. Out-of-equilibrium driving forces typically lead to electronic patterns that are absent at equilibrium, whose nature is however often elusive. Here, we unveil a nanoscale pattern formation in the Ca2 RuO4 Mott insulator. We demonstrate how an applied electric field spatially reconstructs the insulating phase that, uniquely after switching off the electric field, exhibits nanoscale stripe domains. The stripe pattern has regions with inequivalent octahedral distortions that we directly observe through high-resolution scanning transmission electron
microscopy. The nanotexture depends on the orientation of the electric field, it is non-volatile and rewritable. We theoretically simulate the charge and orbital reconstruction induced by a quench dynamics of the applied electric field providing clear-cut mechanisms for the stripe phase formation. Our results open the path for the design of non-volatile electronics based on voltage-controlled nanometric phases. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
001012061600001 |
Publication Date |
2023-05-18 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1530-6984 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
10.8 |
Times cited |
2 |
Open Access |
OpenAccess |
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Notes |
This project has received funding from the European Union’s Horizon 2020 research and innova- tion programme under grant agreement No 823717 – ESTEEM3. The Merlin camera used in the experiment received funding from the FWO-Hercules fund G0H4316N ’Direct electron detector 15for soft matter TEM’. C. A. and G. C. are supported by the Foundation for Polish Science through the International Research Agendas program co-financed by the European Union within the Smart Growth Operational Programme. C. A. and G. C. acknowledge the access to the computing facil- ities of the Interdisciplinary Center of Modeling at the University of Warsaw, Grant No. GB84-0, GB84-1 and GB84-7 and GB84-7 and Poznan Supercomputing and Networking Center Grant No. 609.. C. A. and G. C. acknowledge the CINECA award under the ISCRA initiative IsC85 “TOP- MOST” Grant, for the availability of high-performance computing resources and support. We acknoweldge A. Guarino and C. Elia for providing support about the electrical characterization of the sample. M.C., R.F., and A.V. acknowledge support from the EU’s Horizon 2020213 research and innovation program under Grant Agreement No. 964398 (SUPERGATE). |
Approved |
Most recent IF: 10.8; 2023 IF: 12.712 |
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Call Number |
EMAT @ emat @c:irua:196970 |
Serial |
8789 |
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Permanent link to this record |
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Author |
Conings, B.; Bretschneider, S.A.; Babayigit, A.; Gauquelin, N.; Cardinaletti, I.; Manca, J.V.; Verbeeck, J.; Snaith, H.J.; Boyen, H.-G. |
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Title |
Structure-property relations of methylamine vapor treated hybrid perovskite CH3NH3PbI3 films and solar cells |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
ACS applied materials and interfaces |
Abbreviated Journal |
Acs Appl Mater Inter |
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Volume |
9 |
Issue |
9 |
Pages |
8092-8099 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
The power conversion efficiency of halide perovskite solar cells is heavily dependent on the perovskite layer being sufficiently smooth and pinhole-free. It has been shown that these features can be obtained even when starting out from rough and discontinuous perovskite film, by briefly exposing it to methylamine (MA) vapor. The exact underlying physical mechanisms of this phenomenon are, however, still unclear. By investigating smooth, MA treated films, based on very rough and discontinuous reference films of methylammonium triiode (MAPbI3), considering their morphology, crystalline features, local conductive properties, and charge carrier lifetime, we unravel the relation between their characteristic physical qualities and their performance in corresponding solar cells. We discover that the extensive improvement in photovoltaic performance upon MA treatment is a consequence of the induced morphological enhancement of the perovskite layer, together with improved electron injection into TiO2, which in fact compensates for an otherwise compromised bulk electronic quality, simultaneously caused by the MA treatment. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000396186000025 |
Publication Date |
2017-02-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1944-8244 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
7.504 |
Times cited |
43 |
Open Access |
OpenAccess |
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Notes |
This work was financially supported by BOF (Hasselt University) and the Research Fund Flanders (FWO). B.C. is a postdoctoral research fellow of the FWO. A.B. is financially supported by FWO and Imec. J.V. and N.G. acknowledge funding from GOA project “Solarpaint” of the University of Antwerp and FWO project G.0044.13N “Charge ordering”. The Qu-Ant-EM microscope used for this study was partly funded by the Hercules fund from the Flemish Government. The authors thank Tim Vangerven for Urbach energy determination, and Johnny Baccus and Jan Mertens for technical support. |
Approved |
Most recent IF: 7.504 |
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Call Number |
EMAT @ emat @ c:irua:140849 |
Serial |
4422 |
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Permanent link to this record |
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Author |
Herzog, M.J.; Gauquelin, N.; Esken, D.; Verbeeck, J.; Janek, J. |
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Title |
Increased Performance Improvement of Lithium-Ion Batteries by Dry Powder Coating of High-Nickel NMC with Nanostructured Fumed Ternary Lithium Metal Oxides |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
ACS applied energy materials |
Abbreviated Journal |
ACS Appl. Energy Mater. |
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Volume |
4 |
Issue |
9 |
Pages |
8832-8848 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Dry powder coating is an effective approach to protect the surfaces of layered cathode active materials (CAMs) in lithium-ion batteries. Previous investigations indicate an incorporation of lithium ions in fumed Al2O3, ZrO2, and TiO2 coatings on LiNi0.7Mn0.15Co0.15O2 during cycling, improving the cycling performance. Here, this coating approach is transferred for the first time to fumed ternary LiAlO2, Li4Zr3O8, and Li4Ti5O12 and directly compared with their lithium-free equivalents. All materials could be processed equally and their nanostructured small aggregates accumulate on the CAM surfaces to quite homogeneous coating layers with a certain porosity. The LiNixMnyCozO2 (NMC) coated with lithium-containing materials shows an enhanced improvement in overall capacity, capacity retention, rate performance, and polarization behavior during cycling, compared to their lithium-free analogues. The highest rate performance was achieved with the fumed ZrO2 coating, while the best long-term cycling stability with the highest absolute capacity was obtained for the fumed LiAlO2-coated NMC. The optimal coating agent for NMC to achieve a balanced system is fumed Li4Ti5O12, providing a good compromise between high rate capability and good capacity retention. The coating agents prevent CAM particle cracking and degradation in the order LiAlO2 ≈ Al2O3 > Li4Ti5O12 > Li4Zr3O8 > ZrO2 > TiO2. A schematic model for the protection and electrochemical performance enhancement of high-nickel NMC with fumed metal oxide coatings is sketched. It becomes apparent that physical and chemical characteristics of the coating significantly influence the performance of NMC. A high degree of coating-layer porosity is favorable for the rate capability, while a high coverage of the surface, especially in vulnerable grain boundaries, enhances the long-term cycling stability and improves the cracking behavior of NMCs. While zirconium-containing coatings possess the best chemical properties for high rate performances, aluminum-containing coatings feature a superior chemical nature to protect high-nickel NMCs. |
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Wos |
000703338600018 |
Publication Date |
2021-09-27 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2574-0962 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
15 |
Open Access |
OpenAccess |
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Notes |
For his support in scanning electron microscopy analysis, the authors thank Erik Peldszus. N. G. and J. V. acknowledge funding from GOA project “Solarpaint” of the University of Antwerp and from the Flemish Research Fund (FWO) project G0F1320N. The Qu-Ant-EM microscope and the direct electron detector were partly funded by the Hercules fund from the Flemish Government |
Approved |
Most recent IF: NA |
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Call Number |
EMAT @ emat @c:irua:183949 |
Serial |
6823 |
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Permanent link to this record |
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Author |
Jannis, D.; Müller-Caspary, K.; Béché, A.; Verbeeck, J. |
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Title |
Coincidence Detection of EELS and EDX Spectral Events in the Electron Microscope |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
Applied Sciences-Basel |
Abbreviated Journal |
Appl Sci-Basel |
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Volume |
11 |
Issue |
19 |
Pages |
9058 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Recent advances in the development of electron and X-ray detectors have opened up the possibility to detect single events from which its time of arrival can be determined with nanosecond resolution. This allows observing time correlations between electrons and X-rays in the transmission electron microscope. In this work, a novel setup is described which measures individual events using a silicon drift detector and digital pulse processor for the X-rays and a Timepix3 detector for the electrons. This setup enables recording time correlation between both event streams while at the same time preserving the complete conventional electron energy loss (EELS) and energy dispersive X-ray (EDX) signal. We show that the added coincidence information improves the sensitivity for detecting trace elements in a matrix as compared to conventional EELS and EDX. Furthermore, the method allows the determination of the collection efficiencies without the use of a reference sample and can subtract the background signal for EELS and EDX without any prior knowledge of the background shape and without pre-edge fitting region. We discuss limitations in time resolution arising due to specificities of the silicon drift detector and discuss ways to further improve this aspect. |
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Wos |
000710160300001 |
Publication Date |
2021-09-28 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2076-3417 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.679 |
Times cited |
9 |
Open Access |
OpenAccess |
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Notes |
Fonds Wetenschappelijk Onderzoek, G042920 ; Horizon 2020 Framework Programme, 101017720 ; Helmholtz-Fonds, VH-NG-1317 ; |
Approved |
Most recent IF: 1.679 |
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Call Number |
EMAT @ emat @c:irua:183336 |
Serial |
6821 |
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Permanent link to this record |
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Author |
Abakumov, A.M.; Morozov, V.A.; Tsirlin, A.A.; Verbeeck, J.; Hadermann, J. |
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Title |
Cation ordering and flexibility of the BO42- tetrahedra in incommensurately modulated CaEu2(BO4)4 (B = Mo, W) scheelites |
Type |
A1 Journal article |
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Year |
2014 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
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Volume |
53 |
Issue |
17 |
Pages |
9407-9415 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The factors mediating cation ordering in the scheelite-based molybdates and tungstates are discussed on the basis of the incommensurately modulated crystal structures of the CaEu2(BO4)(4) (B = Mo, W) red phosphors solved from high-resolution synchrotron powder X-ray diffraction data. Monoclinic CaEu2(WO4)(4) adopts a (3 + 1)-dimensionally modulated structure [superspace group I2/b(alpha beta 0)00, a = 5.238 73(1)A, b = 5.266 35(1) A, c = 11.463 19(9) A, gamma = 91.1511(2)degrees, q = 0.56153(6)a* + 0.7708(9)b*, R-F = 0.050, R-p = 0.069], whereas tetragonal CaEu2(MoO4)(4) is (3 + 2)-dimensionally modulated [superspace group I4(1)/ a(alpha beta 0)00(-beta alpha 0)00, a = 5.238 672(7) A, c = 11.548 43(2) A, q(1) = 035331(8)a* + 0.82068(9)b*, q(2) = -0.82068(9)a* + 0.55331(8)b*, R-F = 0.061, R-p = 0.082]. In both cases the modulation arises from the ordering of the Ca/Eu cations and the cation vacancies at the A-sublattice of the parent scheelite ABO(4) structure. The cation ordering is incomplete and better described with harmonic rather than with steplike occupational modulation functions. The structures respond to the variation of the effective charge and cation size at the A-position through the flexible geometry of the MoO42- and WO42- tetrahedra demonstrating an alternation of stretching the B-O bond lengths and bending the O-B-O bond angles. The tendency towards A-site cation ordering in scheelites is rationalized using the difference in ionic radii and concentration of the A-site vacancies as parameters and presented in the form of a structure map. |
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Place of Publication |
Easton, Pa |
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Wos |
000341229600068 |
Publication Date |
2014-08-21 |
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Series Issue |
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Edition |
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ISSN |
0020-1669;1520-510X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.857 |
Times cited |
48 |
Open Access |
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Notes |
Fwo G039211n |
Approved |
Most recent IF: 4.857; 2014 IF: 4.762 |
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Call Number |
UA @ lucian @ c:irua:119292UA @ admin @ c:irua:119292 |
Serial |
297 |
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Permanent link to this record |
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Author |
Liao, Z.; Gauquelin, N.; Green, R.J.; Müller-Caspary, K.; Lobato, I.; Li, L.; Van Aert, S.; Verbeeck, J.; Huijben, M.; Grisolia, M.N.; Rouco, V.; El Hage, R.; Villegas, J.E.; Mercy, A.; Bibes, M.; Ghosez, P.; Sawatzky, G.A.; Rijnders, G.; Koster, G. |
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Title |
Metal–insulator-transition engineering by modulation tilt-control in perovskite nickelates for room temperature optical switching |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
America |
Abbreviated Journal |
P Natl Acad Sci Usa |
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Volume |
115 |
Issue |
38 |
Pages |
9515-9520 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
In transition metal perovskites ABO3 the physical properties are largely driven by the rotations of the BO6 octahedra, which can be tuned in thin films through strain and dimensionality control. However, both approaches have fundamental and practical limitations due to discrete and indirect variations in bond angles, bond lengths and film symmetry by using commercially available substrates. Here, we introduce modulation tilt control as a new approach to tune the ground state of perovskite oxide thin films by acting explicitly on the oxygen octahedra rotation modes, i.e. directly on the bond angles. By intercalating the prototype SmNiO3 target material with a tilt-control layer, we cause the system to change the natural amplitude of a given rotation mode without affecting the interactions. In contrast to strain and dimensionality engineering, our method enables a continuous fine-tuning of the materials properties. This is achieved through two independent adjustable parameters: the nature of the tilt-control material (through its symmetry, elastic constants and oxygen rotation angles) and the relative thicknesses of the target and tilt-control materials. As a result, a magnetic and electronic phase diagram can be obtained, normally only accessible by A-site element substitution, within the single SmNiO3 compound. With this unique approach, we successfully adjusted the metal-insulator transition (MIT) to room temperature to fulfill the desired conditions for optical switching applications. |
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Wos |
000447224900057 |
Publication Date |
2018-09-05 |
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Edition |
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ISSN |
0027-8424 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.661 |
Times cited |
50 |
Open Access |
OpenAccess |
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Notes |
We would like to acknowledge Prof. Z. Zhong for stimulated discussion. M.H., G.K. and G.R. acknowledge funding from DESCO program of the Dutch Foundation for Fundamental Research on Matter (FOM) with financial support from the Netherlands Organization for Scientific Research (NWO). This work was funded by the European Union Council under the 7th Framework Program (FP7) grant nr NMP3-LA-2010-246102 IFOX. J.V., S.V.A, N.G. and K.M.C. acknowledge funding from FWO projects G.0044.13N, G.0374.13N, G. 0368.15N, and G.0369.15N. The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government. N.G. acknowledges funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant 278510 VORTEX. N.G. and J.V. acknowledge financial support from the European Union under the Seventh Framework Program under a contract for an Integrated Infrastructure Initiative (Reference No. 312483- ESTEEM2). The Canadian work was supported by NSERC and the Max Planck-UBC Centre for Quantum Materials. Some experiments for this work were performed at the Canadian Light Source, which is funded by the Canada Foundation for Innovation, NSERC, the National Research Council of Canada, the Canadian Institutes of Health Research, the Government of Saskatchewan, Western Economic Diversification Canada, and the University of Saskatchewan. MB acknowledges funding from the European Research Council under the 7th Framework Program (FP7), ERC CoG grant MINT #615759. A.M. and Ph.G. were supported by the ARC project AIMED and F.R.S-FNRS PDR project HiT4FiT and acknowledge access to Céci computing facilities funded by F.R.S-FNRS (Grant No 2.5020.1), Tier-1 supercomputer of the Fédération Wallonie-Bruxelles funded by the Walloon Region (Grant No 1117545) and HPC resources from the PRACE project Megapasta. |
Approved |
Most recent IF: 9.661 |
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Call Number |
EMAT @ emat @c:irua:154784UA @ admin @ c:irua:154784 |
Serial |
5059 |
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Permanent link to this record |