Records |
Author |
Grieten, E.; Schalm, O.; Tack, P.; Bauters, S.; Storme, P.; Gauquelin, N.; Caen, J.; Patelli, A.; Vincze, L.; Schryvers, D. |
Title |
Reclaiming the image of daguerreotypes: Characterization of the corroded surface before and after atmospheric plasma treatment |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Journal of cultural heritage |
Abbreviated Journal |
J Cult Herit |
Volume |
|
Issue |
|
Pages |
|
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Art; History; Electron microscopy for materials research (EMAT); Antwerp Cultural Heritage Sciences (ARCHES) |
Abstract |
Technological developments such as atmospheric plasma jets for industry can be adapted for the conservation of cultural heritage. This application might offer a potential method for the removal or transformation of the corrosion on historical photographs. We focus on daguerreotypes and present an in-depth study of the induced changes by a multi-analytical approach using optical microscopy, scanning electron microscopy, different types of transmission electron microscopy and X-ray absorption fine structure. The H2-He afterglow removes S from an Ag2S or Cu2S layer which results in a nano-layer of metallic Ag or Cu on top of the deteriorated microstructure. In case the corrosion layer is composed of Cu-Ag-S compounds, our proposed setup can be used to partially remove the corrosion. These alterations of the corrosion results in an improvement in the readability of the photographic image. |
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 |
000414230700007 |
Publication Date |
2017-06-16 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1296-2074 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.838 |
Times cited |
9 |
Open Access |
Not_Open_Access |
Notes |
The authors thank Herman Maes for the daguerreotypes used in this study. The authors also acknowledge the opportunity to perform XAFS measurements at the DUBBLE beamline of the ESRF storage ring under the approval of the advisory Committee (beam time nr. 26-01-990) and acknowledge the DUBBLE beamline staff for their support. They are also grateful for the financial support by the EU-FP7 grant PANNA no. 282998 and the STIMPRO project FFB150215 of the University of Antwerp. Pieter Tack is funded by a Ph.D. grant of the Agency for Innovation by Science and Technology (IWT). |
Approved |
Most recent IF: 1.838 |
Call Number |
EMAT @ emat @c:irua:144430 |
Serial |
4625 |
Permanent link to this record |
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|
|
Author |
Lin, N.S.; Misko, V.R.; Heitmann, T.W.; Yu, K.; Plourde, B.L.T. |
Title |
Density dependence of the rectification of vortex motion in a circular asymmetric channel |
Type |
A1 Journal article |
Year |
2012 |
Publication |
Physica: C : superconductivity |
Abbreviated Journal |
Physica C |
Volume |
479 |
Issue |
|
Pages |
137-139 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We study the rectification of vortex motion in an asymmetric ring channel in a Corbino setup. With an applied ac current, the motion of vortices in the channel is rectified by the asymmetric potential and induces a dc net flow. The net flow in such a system strongly depends on vortex density, and we distinguish “single-vortex'' rectification regime (for low density, when each vortex is rectified individually) determined by the potential-energy landscape inside each cell of the channel and ”multi-vortex'', or "collective'', rectification (high density case) when the interaction between vortices becomes important. (C) 2012 Elsevier B.V. All rights reserved. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000308580600032 |
Publication Date |
2012-01-06 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0921-4534; |
ISBN |
|
Additional Links |
UA library record; WoS full record |
Impact Factor |
1.404 |
Times cited |
|
Open Access |
|
Notes |
; This work was supported by the "Odysseus'' Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl), the Interuniversity Attraction Poles (IAP) Programme – Belgian State – Belgian Science Policy, and the FWO-Vl (Belgium). ; |
Approved |
Most recent IF: 1.404; 2012 IF: 0.718 |
Call Number |
UA @ lucian @ c:irua:101873 |
Serial |
635 |
Permanent link to this record |
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|
Author |
Lin, N.S.; Misko, V.R.; Peeters, F.M. |
Title |
Dynamics of multishell vortex structures in mesoscopic superconducting Corbino disks |
Type |
A1 Journal article |
Year |
2010 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
81 |
Issue |
13 |
Pages |
134504,1-134504,11 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We study the dynamics of vortex shells in mesoscopic superconducting Corbino disks, where vortices form shells as recently observed in micrometer-sized Nb disks. Due to the interplay between the vortex-vortex interaction, the gradient Lorentz force and the (in)commensurability between the numbers of vortices in shells, the process of angular melting of vortex-shell configurations becomes complex. Angular melting can start either from the center of the disk (where the shear stress is maximum) or from its boundary (where the shear stress is minimum) depending on the specific vortex configuration. Furthermore, we found that two kinds of defects can exist in such vortex-shell structures: intrashell and intershell defects. An intrashell defect may lead to an inverse dynamic behavior, i.e., one of the vortex shells under a stronger driving force can rotate slower than the adjacent shell that is driven by a weaker Lorentz force. An intershell defect always locks more than two shells until the gradient of the Lorentz force becomes large enough to break the rigid-body rotation of the locked shells. Such a lock-unlock process leads to hysteresis in the angular velocities of the shells. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
|
Editor |
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Language |
|
Wos |
000277207900079 |
Publication Date |
2010-04-02 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
11 |
Open Access |
|
Notes |
; This work was supported by the “Odysseus” program of the Flemish Government and the Flemish Science Foundation (FWO-V1), the Interuniversity Attraction Poles (IAP) Programme-Belgian State-Belgian Science Policy, and the FWO-V1. ; |
Approved |
Most recent IF: 3.836; 2010 IF: 3.774 |
Call Number |
UA @ lucian @ c:irua:82803 |
Serial |
779 |
Permanent link to this record |
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|
|
Author |
Pogosov, W.V.; Lin, N.; Misko, V.R. |
Title |
Electron-hole symmetry and solutions of Richardson pairing model |
Type |
A1 Journal article |
Year |
2013 |
Publication |
European physical journal : B : condensed matter and complex systems |
Abbreviated Journal |
Eur Phys J B |
Volume |
86 |
Issue |
5 |
Pages |
235-236 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Richardson approach provides an exact solution of the pairing Hamiltonian. This Hamiltonian is characterized by the electron-hole pairing symmetry, which is however hidden in Richardson equations. By analyzing this symmetry and using an additional conjecture, fulfilled in solvable limits, we suggest a simple expression of the ground state energy for an equally-spaced energy-level model, which is applicable along the whole crossover from the superconducting state to the pairing fluctuation regime. Solving Richardson equations numerically, we demonstrate a good accuracy of our expression. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Berlin |
Editor |
|
Language |
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Wos |
000320286200044 |
Publication Date |
2013-05-28 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1434-6028;1434-6036; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.461 |
Times cited |
6 |
Open Access |
|
Notes |
; This work was supported by the “Odysseus” Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). W.V.P. acknowledges useful discussions with Monique Combescot and the support from the Dynasty Foundation, the RFBR (project No. 12-02-00339), and RFBR-CNRS programme (project No. 12-02-91055). ; |
Approved |
Most recent IF: 1.461; 2013 IF: 1.463 |
Call Number |
UA @ lucian @ c:irua:109657 |
Serial |
935 |
Permanent link to this record |
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|
|
Author |
Lin, N.S.; Heitmann, T.W.; Yu, K.; Plourde, B.L.T.; Misko, V.R. |
Title |
Rectification of vortex motion in a circular ratchet channel |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
84 |
Issue |
14 |
Pages |
144511-144511,12 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We study the dynamics of vortices in an asymmetric (i.e., consisting of triangular cells) ring channel driven by an external ac current I in a Corbino setup. The asymmetric potential rectifies the motion of vortices and induces a net vortex flow without any unbiased external drive, i.e., the ratchet effect. We show that the net flow of vortices strongly depends on vortex density and frequency of the driving current. Depending on the density, we distinguish a single-vortex rectification regime (for low density, when each vortex is rectified individually) determined by the potential-energy landscape inside each cell of the channel (i.e., hard and easy directions) and multi-vortex, or collective, rectification (high-density case) when the inter-vortex interaction becomes important. We analyze the average angular velocity ω of vortices as a function of I and study commensurability effects between the numbers of vortices and cells in the channel and the role of frequency of the applied ac current. We have shown that the commensurability effect results in a stepwise ω-I curve. Besides the integer steps, i.e., the large steps found in the single-vortex case, we also found fractional steps corresponding to fractional ratios between the numbers of vortices and triangular cells. We have performed preliminary measurements on a device containing a single weak-pinning circular ratchet channel in a Corbino geometry and observed a substantial asymmetric vortex response. |
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 |
000295795500010 |
Publication Date |
2011-10-07 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
27 |
Open Access |
|
Notes |
; We thank Peter Kes and Marcel Hesselberth for providing the superconducting films from which the Corbino ratchet sample was fabricated. This work was supported by the “Odysseus” Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl), the Interuniversity Attraction Poles (IAP) Programme-Belgian State-Belgian Science Policy, and the FWO-Vl (Belgium). T. W. H., K.Y., and B. L. T. P acknowledge support from the National Science Foundation under Grant DMR-0547147 as well as the use of the Cornell NanoScale Facility, a member of the National Nanotechnology Infrastructure Network, which is supported by the National Science Foundation (Grant ECS-0335765). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:92809 |
Serial |
2848 |
Permanent link to this record |
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|
|
Author |
Misko, V.R.; Lin, N.S.; Peeters, F.M. |
Title |
Unconventional dynamics of vortex shells in mesoscopic superconducting corbino disks |
Type |
A1 Journal article |
Year |
2010 |
Publication |
Physica: C : superconductivity |
Abbreviated Journal |
Physica C |
Volume |
470 |
Issue |
19 |
Pages |
939-941 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The dynamics of vortex matter in mesoscopic superconducting Corbino disk is strongly influenced by the discrete vortex structure arranged in shells. While in previous works the vortex dynamics has been studied in large (macroscopic) and in very small mesoscopic disks (containing only few shells), in the intermediate-size regime it is much more complex and unusual, due to: (i) the competition between the vortexvortex interaction and confinement and (ii) (in)commensurability among the vortex shells. We found that the interplay between these effects can result in a very unusual vortex dynamical behavior: (i) unconventional angular melting (i.e., propagating from the boundary, where the shear stress is minimum, towards the center) and (ii) unconventional dynamics of shells (i.e., the inversion of shell velocities with respect to the gradient driving force). This unusual behavior is found for different number of shells. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000282454400059 |
Publication Date |
2010-03-04 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0921-4534; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.404 |
Times cited |
3 |
Open Access |
|
Notes |
; ; |
Approved |
Most recent IF: 1.404; 2010 IF: 1.415 |
Call Number |
UA @ lucian @ c:irua:85036 |
Serial |
3799 |
Permanent link to this record |
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|
|
Author |
Lin, N.S.; Misko, V.R.; Peeters, F.M. |
Title |
Unconventional vortex dynamics in mesoscopic superconducting corbino disks |
Type |
A1 Journal article |
Year |
2009 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
Volume |
102 |
Issue |
19 |
Pages |
197003,1-197003,4 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The discrete shell structure of vortex matter strongly influences the flux dynamics in mesoscopic superconducting Corbino disks. While the dynamical behavior is well understood in large and in very small disks, in the intermediate-size regime it occurs to be much more complex and unusual, due to (in)commensurability between the vortex shells. We demonstrate unconventional vortex dynamics (inversion of shell velocities with respect to the gradient driving force) and angular melting (propagating from the boundary where the shear stress is minimum, towards the center) in mesoscopic Corbino disks. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
New York, N.Y. |
Editor |
|
Language |
|
Wos |
000266207700063 |
Publication Date |
2009-05-14 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0031-9007;1079-7114; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.462 |
Times cited |
18 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 8.462; 2009 IF: 7.328 |
Call Number |
UA @ lucian @ c:irua:77396 |
Serial |
3800 |
Permanent link to this record |
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|
Author |
Egoavil, R.; Gauquelin, N.; Martinez, G.T.; Van Aert, S.; Van Tendeloo, G.; Verbeeck, J. |
Title |
Atomic resolution mapping of phonon excitations in STEM-EELS experiments |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
147 |
Issue |
|
Pages |
1-7 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Atomically resolved electron energy-loss spectroscopy experiments are commonplace in modern aberration-corrected transmission electron microscopes. Energy resolution has also been increasing steadily with the continuous improvement of electron monochromators. Electronic excitations however are known to be delocalized due to the long range interaction of the charged accelerated electrons with the electrons in a sample. This has made several scientists question the value of combined high spatial and energy resolution for mapping interband transitions and possibly phonon excitation in crystals. In this paper we demonstrate experimentally that atomic resolution information is indeed available at very low energy losses around 100 meV expressed as a modulation of the broadening of the zero loss peak. Careful data analysis allows us to get a glimpse of what are likely phonon excitations with both an energy loss and gain part. These experiments confirm recent theoretical predictions on the strong localization of phonon excitations as opposed to electronic excitations and show that a combination of atomic resolution and recent developments in increased energy resolution will offer great benefit for mapping phonon modes in real space. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000343157400001 |
Publication Date |
2014-05-29 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.843 |
Times cited |
22 |
Open Access |
|
Notes |
246102 IFOX; 278510 VORTEX; 246791 COUNTATOMS; Hercules; 312483 ESTEEM2; esteem2jra3 ECASJO; |
Approved |
Most recent IF: 2.843; 2014 IF: 2.436 |
Call Number |
UA @ lucian @ c:irua:118332UA @ admin @ c:irua:118332 |
Serial |
177 |
Permanent link to this record |
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Author |
Stambula, S.; Gauquelin, N.; Bugnet, M.; Gorantla, S.; Turner, S.; Sun, S.; Liu, J.; Zhang, G.; Sun, X.; Botton, G.A. |
Title |
Chemical structure of nitrogen-doped graphene with single platinum atoms and atomic clusters as a platform for the PEMFC electrode |
Type |
A1 Journal article |
Year |
2014 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
Volume |
118 |
Issue |
8 |
Pages |
3890-3900 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
A platform for producing stabilized Pt atoms and clusters through the combination of an N-doped graphene support and atomic layer deposition (ALD) for the Pt catalysts was investigated using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). It was determined, using imaging and spectroscopy techniques, that a wide range of N-dopant types entered the graphene lattice through covalent bonds without largely damaging its structure. Additionally and most notably, Pt atoms and atomic clusters formed in the absence of nanoparticles. This work provides a new strategy for experimentally producing stable atomic and subnanometer cluster catalysts, which can greatly assist the proton exchange membrane fuel cell (PEMFC) development by producing the ultimate surface area to volume ratio catalyst. |
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 |
000332188100004 |
Publication Date |
2014-02-12 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1932-7447;1932-7455; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.536 |
Times cited |
57 |
Open Access |
|
Notes |
Fwo |
Approved |
Most recent IF: 4.536; 2014 IF: 4.772 |
Call Number |
UA @ lucian @ c:irua:115571 |
Serial |
352 |
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.; |
Title |
Crystal Structure and Luminescent Properties of R2-xEux(MoO4)(3) (R = Gd, Sm) Red Phosphors |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
26 |
Issue |
24 |
Pages |
7124-7136 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
|
Editor |
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Language |
|
Wos |
000347139700027 |
Publication Date |
2014-11-27 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
24 |
Open Access |
|
Notes |
Fwo G039211n; G004413n; 278510 Vortex ECASJO_; |
Approved |
Most recent IF: 9.466; 2014 IF: 8.354 |
Call Number |
UA @ lucian @ c:irua:122829UA @ admin @ c:irua:122829 |
Serial |
558 |
Permanent link to this record |
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Author |
Chen, Y.Z.; Trier, F.; Wijnands, T.; Green, R.J.; Gauquelin, N.; Egoavil, R.; Christensen, D.V.; Koster, G.; Huijben, M.; Bovet, N.; Macke, S.; He, F.; Sutarto, R.; Andersen, N.H.; Sulpizio, J.A.; Honig, M.; Prawiroatmodjo, G.E.D.K.; Jespersen, T.S.; Linderoth, S.; Ilani, S.; Verbeeck, J.; Van Tendeloo, G.; Rijnders, G.; Sawatzky, G.A.; Pryds, N. |
Title |
Extreme mobility enhancement of two-dimensional electron gases at oxide interfaces by charge-transfer-induced modulation doping |
Type |
A1 Journal article |
Year |
2015 |
Publication |
Nature materials |
Abbreviated Journal |
Nat Mater |
Volume |
14 |
Issue |
14 |
Pages |
801-806 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Two-dimensional electron gases (2DEGs) formed at the interface of insulating complex oxides promise the development of all-oxide electronic devices. These 2DEGs involve many-body interactions that give rise to a variety of physical phenomena such as superconductivity, magnetism, tunable metalinsulator transitions and phase separation. Increasing the mobility of the 2DEG, however, remains a major challenge. Here, we show that the electron mobility is enhanced by more than two orders of magnitude by inserting a single-unit-cell insulating layer of polar La1−xSrxMnO3 (x = 0, 1/8, and 1/3) at the interface between disordered LaAlO3 and crystalline SrTiO3 produced at room temperature. Resonant X-ray spectroscopy and transmission electron microscopy show that the manganite layer undergoes unambiguous electronic reconstruction, leading to modulation doping of such atomically engineered complex oxide heterointerfaces. At low temperatures, the modulation-doped 2DEG exhibits Shubnikovde Haas oscillations and fingerprints of the quantum Hall effect, demonstrating unprecedented high mobility and low electron density. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
London |
Editor |
|
Language |
|
Wos |
000358530100022 |
Publication Date |
2015-06-01 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1476-1122;1476-4660; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
39.737 |
Times cited |
170 |
Open Access |
|
Notes |
246102 IFOX; 246791 COUNTATOMS; 278510 VORTEX; Hercules; 312483 ESTEEM2; FWO G004413N; esteem2jra3 ECASJO; |
Approved |
Most recent IF: 39.737; 2015 IF: 36.503 |
Call Number |
c:irua:127184 c:irua:127184UA @ admin @ c:irua:127184 |
Serial |
1163 |
Permanent link to this record |
|
|
|
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. |
Title |
Influence of the structure on the properties of NaxEuy(MoO4)z red phosphors |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
26 |
Issue |
10 |
Pages |
3238-3248 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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. |
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 |
|
Language |
|
Wos |
000336637000028 |
Publication Date |
2014-05-01 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
53 |
Open Access |
|
Notes |
Fwo G039211n; Fwo G004413n; 278510 Vortex ECASJO_; |
Approved |
Most recent IF: 9.466; 2014 IF: 8.354 |
Call Number |
UA @ lucian @ c:irua:117765UA @ admin @ c:irua:117765 |
Serial |
1652 |
Permanent link to this record |
|
|
|
Author |
Volkova, N.E.; Lebedev, O.I.; Gavrilova, L.Y.; Turner, S.; Gauquelin, N.; Seikh, M.M.; Caignaert, V.; Cherepanov, V.A.; Raveau, B.; Van Tendeloo, G. |
Title |
Nanoscale ordering in oxygen deficient quintuple perovskite Sm2-\epsilonBa3+\epsilonFe5O15-\delta : implication for magnetism and oxygen stoichiometry |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
26 |
Issue |
21 |
Pages |
6303-6310 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
The investigation of the system SmBaFe-O in air has allowed an oxygen deficient perovskite Sm2-epsilon Ba3+epsilon Fe5O15-delta (delta = 0.75, epsilon = 0.125) to be synthesized. In contrast to the XRPD pattern which gives a cubic symmetry (a(p) = 3.934 angstrom), the combined HREM/EELS study shows that this phase is nanoscale ordered with a quintuple tetragonal cell, a(p) X a(p) X 5(ap). The nanodomains exhibit a unique stacking sequence of the A-site cationic layers along the crystallographic c-axis, namely SmBaBa/SmBa/SmBaSm, and are chemically twinned in the three crystallographic directions. The nanoscale ordering of this perovskite explains its peculiar magnetic properties on the basis of antiferromagnetic interactions with spin blockade at the boundary between the nanodomains. The variation of electrical conductivity and oxygen content of this oxide versus temperature suggest potential SOFC applications. They may be related to the particular distribution of oxygen vacancies in the lattice and to the 3d(5)(L) under bar configuration of iron. |
Address |
|
Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000344905600029 |
Publication Date |
2014-10-07 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
16 |
Open Access |
|
Notes |
The UrFU authors were financially supported by the Ministry of Education and Science of Russian Federation (project N 4.1039.2014/K) and by UrFU under the Framework Program of development of UrFU through the «Young scientists UrFU» competition. The CRISMAT authors gratefully acknowledge the EC, the CNRS and the French Minister of Education and Research for financial support through their Research, Strategic and Scholarship programs. This work was supported by funding from the European Research Council under the Seventh Framework Program (FP7), ERC grant N°246791 – COUNTATOMS. S.T. gratefully acknowledges the fund for scientific research Flanders for a post-doctoral fellowship and for financial support under contract number G004413N. N.G. acknowledges funding from the European Research Council under the 7th Framework Program (FP7), ERC starting grant number 278510 – VORTEX; ECASJO_; |
Approved |
Most recent IF: 9.466; 2014 IF: 8.354 |
Call Number |
UA @ lucian @ c:irua:122137 |
Serial |
2269 |
Permanent link to this record |
|
|
|
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. |
Title |
KEu(MoO4)2 : polymorphism, structures, and luminescent properties |
Type |
A1 Journal article |
Year |
2015 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
27 |
Issue |
27 |
Pages |
5519-5530 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
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Editor |
|
Language |
|
Wos |
000360323700011 |
Publication Date |
2015-07-29 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
26 |
Open Access |
|
Notes |
278510 Vortex; Fwo G039211n; G004413n ECASJO_; |
Approved |
Most recent IF: 9.466; 2015 IF: 8.354 |
Call Number |
c:irua:127244 |
Serial |
3537 |
Permanent link to this record |
|
|
|
Author |
Morozov, V.A.; Arakcheeva, A.V.; Chapuis, G.; Guiblin, N.; Rossell, M.D.; Van Tendeloo, G. |
Title |
KNd(MoO4)2: a new incommensurate modulated structure in the scheelite family |
Type |
A1 Journal article |
Year |
2006 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
18 |
Issue |
17 |
Pages |
4075-4082 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Washington, D.C. |
Editor |
|
Language |
|
Wos |
000239758300022 |
Publication Date |
2006-07-28 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
46 |
Open Access |
|
Notes |
Iap V-1 |
Approved |
Most recent IF: 9.466; 2006 IF: 5.104 |
Call Number |
UA @ lucian @ c:irua:60688 |
Serial |
3538 |
Permanent link to this record |
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|
|
Author |
Liao, Z.; Huijben, M.; Zhong, Z.; Gauquelin, N.; Macke, S.; Green, R.J.; Van Aert, S.; Verbeeck, J.; Van Tendeloo, G.; Held, K.; Sawatzky, G.A.; Koster, G.; Rijnders, G. |
Title |
Controlled lateral anisotropy in correlated manganite heterostructures by interface-engineered oxygen octahedral coupling |
Type |
A1 Journal article |
Year |
2016 |
Publication |
Nature materials |
Abbreviated Journal |
Nat Mater |
Volume |
15 |
Issue |
15 |
Pages |
425-431 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Controlled in-plane rotation of the magnetic easy axis in manganite heterostructures by tailoring the interface oxygen network could allow the development of correlated oxide-based magnetic tunnelling junctions with non-collinear magnetization, with possible practical applications as miniaturized high-switching-speed magnetic random access memory (MRAM) devices. Here, we demonstrate how to manipulate magnetic and electronic anisotropic properties in manganite heterostructures by engineering the oxygen network on the unit-cell level. The strong oxygen octahedral coupling is found to transfer the octahedral rotation, present in the NdGaO3 (NGO) substrate, to the La2/3Sr1/3MnO3 (LSMO) film in the interface region. This causes an unexpected realignment of the magnetic easy axis along the short axis of the LSMO unit cell as well as the presence of a giant anisotropic transport in these ultrathin LSMO films. As a result we possess control of the lateral magnetic and electronic anisotropies by atomic-scale design of the oxygen octahedral rotation. |
Address |
MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands |
Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
|
Editor |
|
Language |
English |
Wos |
000372591700017 |
Publication Date |
2016-03-07 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1476-1122 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
39.737 |
Times cited |
273 |
Open Access |
|
Notes |
We would like to acknowledge Dr. Evert Houwman 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. and S.V.A. acknowledges funding from FWO project G.0044.13N and G. 0368.15N. 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., S.V.A., J.V. and G.V.T. 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. Z.Z. acknowledges funding from the SFB ViCoM (Austrian Science Fund project ID F4103- N13), and Calculations have been done on the Vienna Scientific Cluster (VSC).; esteem2jra2; esteem2jra3 ECASJO_; |
Approved |
Most recent IF: 39.737 |
Call Number |
c:irua:133190 c:irua:133190UA @ admin @ c:irua:133190 |
Serial |
4041 |
Permanent link to this record |
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|
|
Author |
Liao, Z.L.; Green, R.J.; Gauquelin, N.; Gonnissen, J.; Van Aert, S.; Verbeeck, J.; et al. |
Title |
Engineering properties by long range symmetry propagation initiated at perovskite heterostructure interface |
Type |
A1 Journal article |
Year |
2016 |
Publication |
Advanced functional materials |
Abbreviated Journal |
Adv Funct Mater |
Volume |
|
Issue |
|
Pages |
1-25 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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 induce an accompanying change in their properties. In perovskite materials, the crystal symmetry can be described by rotations of 6-fold coordinated transition metal oxygen octahedra, which are found to be altered at interfaces. Here, we unravel how the local oxygen octahedral coupling (OOC) at perovskite heterostructural interfaces initiates a different symmetry in epitaxial films and provide design rules to induce various symmetries in thin films by careful selecting appropriate combinations of substrate/buffer/film. Very interestingly we discovered that these combinations lead to symmetry changes throughout the full thickness of the film. Our results provide a deep insight into understanding the origin of induced crystal symmetry in a perovskite heterostructure and an intelligent route to achieve unique functional properties. |
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 |
|
Language |
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Wos |
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Publication Date |
|
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1616-301x |
ISBN |
|
Additional Links |
UA library record |
Impact Factor |
12.124 |
Times cited |
|
Open Access |
|
Notes |
|
Approved |
Most recent IF: 12.124 |
Call Number |
UA @ lucian @ c:irua:134842 |
Serial |
4176 |
Permanent link to this record |
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|
|
Author |
Jany, B.R.; Gauquelin, N.; Willhammar, T.; Nikiel, M.; van den Bos, K.H.W.; Janas, A.; Szajna, K.; Verbeeck, J.; Van Aert, S.; Van Tendeloo, G.; Krok, F. |
Title |
Controlled growth of hexagonal gold nanostructures during thermally induced self-assembling on Ge(001) surface |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Scientific reports |
Abbreviated Journal |
Sci Rep-Uk |
Volume |
7 |
Issue |
7 |
Pages |
42420 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Nano-sized gold has become an important material in various fields of science and technology, where control over the size and crystallography is desired to tailor the functionality. Gold crystallizes in the face-centered cubic (fcc) phase, and its hexagonal closed packed (hcp) structure is a very unusual and rare phase. Stable Au hcp phase has been reported to form in nanoparticles at the tips of some Ge nanowires. It has also recently been synthesized in the form of thin graphene-supported sheets which are unstable under electron beam irradiation. Here, we show that stable hcp Au 3D nanostructures with well-defined crystallographic orientation and size can be systematically created in a process of thermally induced self-assembly of thin Au layer on Ge(001) monocrystal. The Au hcp crystallite is present in each Au nanostructure and has been characterized by different electron microscopy techniques. We report that a careful heat treatment above the eutectic melting temperature and a controlled cooling is required to form the hcp phase of Au on a Ge single crystal. This new method gives scientific prospects to obtain stable Au hcp phase for future applications in a rather simple manner as well as redefine the phase diagram of Gold with Germanium. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000393940700001 |
Publication Date |
2017-02-14 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
2045-2322 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.259 |
Times cited |
25 |
Open Access |
OpenAccess |
Notes |
The authors gratefully acknowledge the financial support from the Polish National Science Center, grant no. DEC-2012/07/B/ST5/00906. N.G., G.V.T. and J.V. acknowledge the European Union (EU) Council under the 7th Framework Program (FP7) ERC Starting Grant 278510 VORTEX for support. The Research Foundation Flanders is acknowledged through project fundings (G.0374.13N, G.0368.15N, G.0369.15N) and for a Ph.D. research grant to K.H.W.v.d.B. The microscope was partly funded by the Hercules Fund from the Flemish Government. T.W. acknowledges the Swedish Research Council for an international postdoc grant. The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement 312483–ESTEEM2 (Integrated Infrastructure Initiative–I3). Part of the research was carried out with equipment purchased with financial support from the European Regional Development Fund in the framework of the Polish Innovation Economy Operational Program (Contract No. POIG.02.01.00-12-023/08). |
Approved |
Most recent IF: 4.259 |
Call Number |
EMAT @ emat @ c:irua:140846UA @ admin @ c:irua:140846 |
Serial |
4423 |
Permanent link to this record |
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|
|
Author |
Smolin, S.Y.; Choquette, A.K.; Wilks, R.G.; Gauquelin, N.; Félix, R.; Gerlach, D.; Ueda, S.; Krick, A.L.; Verbeeck, J.; Bär, M.; Baxter, J.B.; May, S.J. |
Title |
Energy Level Alignment and Cation Charge States at the LaFeO3/LaMnO3(001) Heterointerface |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Advanced Materials Interfaces |
Abbreviated Journal |
Adv Mater Interfaces |
Volume |
4 |
Issue |
4 |
Pages |
1700183 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
The electronic properties of LaFeO 3 /LaMnO 3 epitaxial heterojunctions are investigated to determine the valence and conduction band offsets and the nominal Mn and Fe valence states at the interface. Studying a systematic series of (LaFeO 3 ) n /(LaMnO 3 ) m bilayers (m ≈ 50) epitaxially grown in the (001) orientation using molecular beam epitaxy, layer-resolved electron energy loss spectroscopy reveals a lack of significant interfacial charge transfer, with a nominal 3+ valence state observed for both Mn and Fe across the interface. Through a combination of variable angle spectroscopic ellipsometry and hard X-ray photoelectron spectroscopy, type I energy level alignments are obtained at the LaFeO 3 /LaMnO 3 interface with positive valence and conduction band offsets of (1.20 ± 0.07) eV and (0.5–0.7 ± 0.3) eV, respectively, with minimal band bending. Variable temperature resistivity measurements reveal that the bilayers remain insulating and that the presence of the heterojunction does not result in a conducting interface. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
|
Editor |
|
Language |
|
Wos |
000406068400011 |
Publication Date |
2017-04-26 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
2196-7350 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.279 |
Times cited |
14 |
Open Access |
Not_Open_Access |
Notes |
The authors thank Dmytro Nykypanchuk for assistance with the near- infrared ellipsometry measurement of the LaMnO 3 film. S.Y.S., A.K.C., J.B.B, and S.J.M. acknowledge funding from the National Science Foundation under grant number ECCS-1201957. S.Y.S. acknowledges additional funding from the German Academic Exchange Service (DAAD) through the Research Internships in Science and Engineering (RISE) professional program 2015 ID 5708457. A.L.K. was funded by the National Science Foundation under grant number DMR-1151649. J.V. and N.G. acknowledge funding through the GOA project “Solarpaint” of the University of Antwerp and from the FWO project G.0044.13N (Charge ordering). The microscope used in this work was partly funded by the Hercules Fund from the Flemish Government. Ellipsometry measurements of the LaMnO 3 film were carried out at the Center for Functional Nanomaterials, Brookhaven National Laboratory, which is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-ACO2-98CH10886. S.U. would like to thank the staff of HiSOR, Hiroshima University, and JAEA/Spring-8 for the development of HAXPES at BL15XU of SPring-8. The HAXPES measurements were performed with approval of NIMS Synchrotron X-ray Station (Proposal No. 2015B4601), and were partly supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. The authors also thank HZB for the allocation of synchrotron radiation beamtime for HAXPES/XANES measurements. R.G.W., R.F, and M.B. are grateful to the Impuls- und Vernetzungsfonds of the Helmholtz Association (VH-NG-423).; National Science Foundation, ECCS-1201957 DMR-1151649 ; Deutscher Akademischer Austauschdienst, 2015 ID 5708457 ; GOA project; Fonds Wetenschappelijk Onderzoek, G.0044.13N ; Flemish Government; U.S. Department of Energy, DE-ACO2-98CH10886 ; Vernetzungsfonds of the Helmholtz Association, VH-NG-423 ; |
Approved |
Most recent IF: 4.279 |
Call Number |
EMAT @ emat @ c:irua:142346UA @ admin @ c:irua:142346 |
Serial |
4553 |
Permanent link to this record |
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|
|
Author |
Gauquelin, N.; van den Bos, K.H.W.; Béché, A.; Krause, F.F.; Lobato, I.; Lazar, S.; Rosenauer, A.; Van Aert, S.; Verbeeck, J. |
Title |
Determining oxygen relaxations at an interface: A comparative study between transmission electron microscopy techniques |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
181 |
Issue |
181 |
Pages |
178-190 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Nowadays, aberration corrected transmission electron microscopy (TEM) is a popular method to characterise nanomaterials at the atomic scale. Here, atomically resolved images of nanomaterials are acquired, where the contrast depends on the illumination, imaging and detector conditions of the microscope. Visualization of light elements is possible when using low angle annular dark field (LAADF) STEM, annular bright field (ABF) STEM, integrated differential phase contrast (iDPC) STEM, negative spherical aberration imaging (NCSI) and imaging STEM (ISTEM). In this work, images of a NdGaO3-La0.67Sr0.33MnO3 (NGO-LSMO) interface are quantitatively evaluated by using statistical parameter estimation theory. For imaging light elements, all techniques are providing reliable results, while the techniques based on interference contrast, NCSI and ISTEM, are less robust in terms of accuracy for extracting heavy column locations. In term of precision, sample drift and scan distortions mainly limits the STEM based techniques as compared to NCSI. Post processing techniques can, however, partially compensate for this. In order to provide an outlook to the future, simulated images of NGO, in which the unavoidable presence of Poisson noise is taken into account, are used to determine the ultimate precision. In this future counting noise limited scenario, NCSI and ISTEM imaging will provide more precise values as compared to the other techniques, which can be related to the mechanisms behind the image recording. |
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Place of Publication |
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Language |
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Wos |
000411170800022 |
Publication Date |
2017-06-03 |
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 |
0304-3991 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.843 |
Times cited |
34 |
Open Access |
OpenAccess |
Notes |
The authors acknowledge financial support from Flanders (FWO, Belgium) through project fundings (G.0044.13N, G.0374.13N, G.0368.15N, G.0369.15N), and by a Ph.D. grant to K.H.W.v.d.B. The Qu-Ant-EM microscope used for this study was partly funded by the Hercules fund from the Flemish Government. A.B. and N.G. acknowledge the EUROTAPES project (FP7-NMP.2011.2.2-1 Grant no.280432) which partly funded this study. N.G., A.B. and J.V. acknowledge funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant 278510 VORTEX. The research leading to these results has received funding from the Deutsche Forschungsgemeinschaft under Contract No. RO 2057/4-2 and the European Union Seventh Framework Programme under Grant Agreement 312483 – ESTEEM2. We thank Prof. G. Koster from the University of Twente for kindly providing us with the LSMO-NGO test sample. |
Approved |
Most recent IF: 2.843 |
Call Number |
EMAT @ emat @ c:irua:144435UA @ admin @ c:irua:144435 |
Serial |
4620 |
Permanent link to this record |
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Author |
Li, L.; Liao, Z.; Gauquelin, N.; Minh Duc Nguyen; Hueting, R.J.E.; Gravesteijn, D.J.; Lobato, I.; Houwman, E.P.; Lazar, S.; Verbeeck, J.; Koster, G.; Rijnders, G. |
Title |
Epitaxial stress-free growth of high crystallinity ferroelectric PbZr0.52Ti0.48O3 on GaN/AlGaN/Si(111) substrate |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Advanced Materials Interfaces |
Abbreviated Journal |
Adv Mater Interfaces |
Volume |
5 |
Issue |
2 |
Pages |
1700921 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
<script type='text/javascript'>document.write(unpmarked('Due to its physical properties gallium-nitride (GaN) is gaining a lot of attention as an emerging semiconductor material in the field of high-power and high-frequency electronics applications. Therefore, the improvement in the performance and/or perhaps even extension in functionality of GaN based devices would be highly desirable. The integration of ferroelectric materials such as lead-zirconate-titanate (PbZrxTi1-xO3) with GaN has a strong potential to offer such an improvement. However, the large lattice mismatch between PZT and GaN makes the epitaxial growth of Pb(Zr1-xTix)O-3 on GaN a formidable challenge. This work discusses a novel strain relaxation mechanism observed when MgO is used as a buffer layer, with thicknesses down to a single unit cell, inducing epitaxial growth of high crystallinity Pb(Zr0.52Ti0.48)O-3 (PZT) thin films. The epitaxial PZT films exhibit good ferroelectric properties, showing great promise for future GaN device applications.')); |
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Place of Publication |
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Wos |
000423173800005 |
Publication Date |
2017-11-27 |
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 |
2196-7350 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.279 |
Times cited |
15 |
Open Access |
Not_Open_Access |
Notes |
; L.L., Z.L.L., and N.G. contributed equally to this work. L.L. acknowledges financial support from Nano Next NL (Grant no. 7B 04). The authors acknowledge NXP for providing the GaN/AlGaN/Si (111) wafer. N.G. acknowledges funding from the Geconcentreerde Onderzoekacties (GOA) project “Solarpaint” of the University of Antwerp and J.V. acknowledges funding from the Research Foundation Flanders (FWO, Belgium) project 42/FA070100/6088 “nieuwe eigenschappen in complexe Oxides.” N.G. acknowledges the EUROTAPES project (FP7-NMP.2011.2.2-1 Grant no. 280432) which partly funded this study. ; |
Approved |
Most recent IF: 4.279 |
Call Number |
UA @ lucian @ c:irua:148427UA @ admin @ c:irua:148427 |
Serial |
4872 |
Permanent link to this record |
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Author |
Groenendijk, D.J.; Autieri, C.; Girovsky, J.; Martinez-Velarte, M.C.; Manca, N.; Mattoni, G.; Monteiro, A.M.R.V.L.; Gauquelin, N.; Verbeeck, J.; Otte, A.F.; Gabay, M.; Picozzi, S.; Caviglia, A.D. |
Title |
Spin-orbit semimetal SrIrO3 in the two-dimensional limit |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
Volume |
119 |
Issue |
25 |
Pages |
256403 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
<script type='text/javascript'>document.write(unpmarked('We investigate the thickness-dependent electronic properties of ultrathin SrIrO3 and discover a transition from a semimetallic to a correlated insulating state below 4 unit cells. Low-temperature magnetoconductance measurements show that spin fluctuations in the semimetallic state are significantly enhanced while approaching the transition point. The electronic properties are further studied by scanning tunneling spectroscopy, showing that 4 unit cell SrIrO(3)d is on the verge of a gap opening. Our density functional theory calculations reproduce the critical thickness of the transition and show that the opening of a gap in ultrathin SrIrO3 requires antiferromagnetic order.')); |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000418619100014 |
Publication Date |
2017-12-22 |
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 |
0031-9007 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.462 |
Times cited |
79 |
Open Access |
OpenAccess |
Notes |
; This work was supported by The Netherlands Organisation for Scientific Research (NWO/OCW) as part of the Frontiers of Nanoscience program (NanoFront), by the Dutch Foundation for Fundamental Research on Matter (FOM), and by the European Research Council under the European Union's H2020 programme/ERC Grant Agreement No. [677458]. The authors thank R. Claessen, P. Schutz, D. Di Sante, G. Sangiovanni, and A. Santander Syro for useful discussions. M. G. gratefully acknowledges support from the French National Research Agency (ANR) (Project LACUNES No. ANR-13-BS04-0006-01). C. A. and S. P. acknowledge financial support from Fondazione Cariplo via the project Magister (Project No. 2013-0726) and from CNR-SPIN via the Seed Project “CAMEO”. N. G. and J. V. acknowledge support from the GOA project “Solarpaint” of the University of Antwerp. The Qu-AntEM microscope was partly funded by the Hercules fund from the Flemish Government. ; |
Approved |
Most recent IF: 8.462 |
Call Number |
UA @ lucian @ c:irua:148510 |
Serial |
4897 |
Permanent link to this record |
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Author |
Zhang, H.; Gauquelin, N.; McMahon, C.; Hawthorn, D.G.; Botton, G.A.; Wei, J.Y.T. |
Title |
Synthesis of high-oxidation Y-Ba-Cu-O phases in superoxygenated thin films |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Physical review materials |
Abbreviated Journal |
|
Volume |
2 |
Issue |
3 |
Pages |
033803 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
It is known that solid-state reaction in high-pressure oxygen can stabilize high-oxidation phases of Y-Ba-Cu-O superconductors in powder form. We extend this superoxygenation concept of synthesis to thin films which, due to their large surface-to-volume ratio, are more reactive thermodynamically. Epitaxial thin films of YBa2Cu3O7-delta grown by pulsed laser deposition are annealed at up to 700 atm O-2 and 900 degrees C, in conjunction with Cu enrichment by solid-state diffusion. The films show the clear formation of Y2Ba4Cu7O15-delta and Y2Ba4Cu8O16 as well as regions of YBa2Cu5O9-delta and YBa2Cu6O10-delta phases, according to scanning transmission electron microscopy, x-ray diffraction, and x-ray absorption spectroscopy. Similarly annealed YBa2Cu3O7-delta powders show no phase conversion. Our results demonstrate a route of synthesis towards discovering more complex phases of cuprates and other superconducting oxides. |
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Corporate Author |
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Thesis |
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Publisher |
American Physical Society |
Place of Publication |
College Park, Md |
Editor |
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Language |
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Wos |
000428244900004 |
Publication Date |
2018-03-26 |
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 |
2475-9953 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
|
Times cited |
2 |
Open Access |
Not_Open_Access |
Notes |
; This work is supported by NSERC, CFI-OIT, and CIFAR. The electron microscopy work was carried out at the Canadian Centre for Electron Microscopy, a National Facility supported by the Canada Foundation for Innovation under the Major Science Initiative program, McMaster University, and NSERC. The XAS work was performed at the Canadian Light Source, which is supported by NSERC, NRC, CIHR, and the University of Saskatchewan. ; |
Approved |
Most recent IF: NA |
Call Number |
UA @ lucian @ c:irua:150829 |
Serial |
4982 |
Permanent link to this record |
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Author |
Bhat, S.G.; Gauquelin, N.; Sebastian, N.K.; Sil, A.; Béché, A.; Verbeeck, J.; Samal, D.; Kumar, P.S.A. |
Title |
Orthorhombic vs. hexagonal epitaxial SrIrO3 thin films : structural stability and related electrical transport properties |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Europhysics letters |
Abbreviated Journal |
Epl-Europhys Lett |
Volume |
122 |
Issue |
2 |
Pages |
28003 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Metastable orthorhombic SrIrO3 (SIO) is an arch-type spin-orbit coupled material. We demonstrate here a controlled growth of relatively thick (200 nm) SIO films that transform from bulk “6H-type” structure with monoclinic distortion to an orthorhombic lattice by controlling growth temperature. Extensive studies based on high-resolution X-ray diffraction and transmission electron microscopy infer a two distinct structural phases of SIO. Electrical transport reveals a weak temperature-dependent semi-metallic character for both phases. However, the temperature-dependent Hall-coefficient for the orthorhombic SIO exhibits a prominent sign change, suggesting a multiband character in the vicinity of E-F. Our findings thus unravel the subtle structure-property relation in SIO epitaxial thin films. Copyright (C) EPLA, 2018 |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Paris |
Editor |
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Language |
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Wos |
000435517300001 |
Publication Date |
2018-06-18 |
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 |
0295-5075 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.957 |
Times cited |
4 |
Open Access |
Not_Open_Access |
Notes |
; SGB and DS acknowledge useful discussions with E. P. Houwman, University of Twente, on X-ray diffraction. DS would like to thank H. Takagi, Max-Planck Institute for Solid State Research, Stuttgart, for the fruitful discussion on the transport properties of SIO thin films. SGB and NKS thank A. Aravind, Bishop Moore College, Mavelikara, for his valuable inputs while depositing the thin films of SIO. SGB, NKS and PSAK acknowledge Nano Mission Council, Department of Science & Technology, India, for the funding. DS acknowledges the financial support from Max-Planck Society through MaxPlanck Partner Group. NG, AB and JV acknowledge funding from GOA project “Solarpaint” of the University of Antwerp and FWO project G093417N. ; |
Approved |
Most recent IF: 1.957 |
Call Number |
UA @ lucian @ c:irua:152074UA @ admin @ c:irua:152074 |
Serial |
5034 |
Permanent link to this record |
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Author |
Hasanli, N.; Gauquelin, N.; Verbeeck, J.; Hadermann, J.; Hayward, M.A. |
Title |
Small-moment paramagnetism and extensive twinning in the topochemically reduced phase Sr2ReLiO5.5 |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Journal of the Chemical Society : Dalton transactions |
Abbreviated Journal |
Dalton T |
Volume |
47 |
Issue |
44 |
Pages |
15783-15790 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Reaction of the cation-ordered double perovskite Sr2ReLiO6 with dilute hydrogen at 475 degrees C leads to the topochemical deintercalation of oxide ions from the host lattice and the formation of a phase of composition Sr2ReLiO5.5, as confirmed by thermogravimetric and EELS data. A combination of neutron and electron diffraction data reveals the reduction process converts the -Sr2O2-ReLiO4-Sr2O2-ReLiO4- stacking sequence of the parent phase into a -Sr2O2-ReLiO3-Sr2O2-ReLiO4-, partially anion-vacant ordered sequence. Furthermore a combination of electron diffraction and imaging reveals Sr2ReLiO5.5 exhibits extensive twinning – a feature which can be attributed to the large, anisotropic volume expansion of the material on reduction. Magnetisation data reveal a strongly reduced moment of (eff) = 0.505(B) for the d(1) Re6+ centres in the phase, suggesting there remains a large orbital component to the magnetism of the rhenium centres, despite their location in low symmetry coordination environments. |
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Corporate Author |
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Publisher |
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Place of Publication |
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Language |
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Wos |
000450208000019 |
Publication Date |
2018-10-18 |
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 |
1477-9226 |
ISBN |
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Additional Links |
UA library record; WoS full record |
Impact Factor |
4.029 |
Times cited |
|
Open Access |
Not_Open_Access |
Notes |
Experiments at the Diamond Light Source were performed as part of the Block Allocation Group award “Oxford Solid State Chemistry BAG to probe composition-structure-property relationships in solids” (EE13284). Experiments at the ISIS pulsed neutron facility were supported by a beam time allocation from the STFC. NH acknowledges funding from the “State Programme on Education of Azerbaijani Youth Abroad in 2007-2015” by the Ministry of Education of Azerbaijan. J. V. and N. G. acknowledge funding through the GOA project “Solarpaint” of the University of Antwerp. The microscope used in this work was partly funded by the Hercules Fund from the Flemish Government. |
Approved |
Most recent IF: 4.029 |
Call Number |
EMAT @ emat @c:irua:155771 |
Serial |
5137 |
Permanent link to this record |
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Author |
Godet, M.; Vergès-Belmin, V.; Gauquelin, N.; Saheb, M.; Monnier, J.; Leroy, E.; Bourgon, J.; Verbeeck, J.; Andraud, C. |
Title |
Nanoscale investigation by TEM and STEM-EELS of the laser induced yellowing |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Micron |
Abbreviated Journal |
Micron |
Volume |
115 |
Issue |
|
Pages |
25-31 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Nd-YAG QS laser cleaning of soiled stone at 1064 nm can sometimes result in a more yellow appearance compared to other cleaning techniques. Especially in France, this yellowing effect is still considered as a major aesthetic issue by the architects and conservators. One explanation states that the yellowing is linked to the formation of iron-rich nanophase(s) through the laser beam interaction with black crusts that would re-deposit on the cleaned substrate after irradiation. To characterize these nanophases, a model crust containing hematite was elaborated and laser irradiated using a Nd-YAG QS laser. The color of the sample shifted instantaneously from red to a bright yellow and numerous particles were ablated in a visible smoke. Transmission electron microscopy (TEM) was used to examine the morphology and the crystallinity of the neo-formed compounds, both on the surface of the samples and in the ablated materials. In addition, an investigation of the chemical and structural properties of the nanophases was conducted by X-ray dispersive energy (EDX) and electron energy loss (EELS) spectroscopies. It was found that both the surface of the sample and the ablated materials are covered by crystallized nano-spheres and nano-residues, all containing iron and oxygen, sometimes along with calcium and sulfur. In particular an interfacial area containing the four elements was evidenced between some nanostructures and the substrate. Magnetite Fe3O4 was also identified at the nanoscale. This study demonstrates that the laser yellowing of a model crust is linked to the presence of iron-rich nanophases including CaxFeySzOδ nanostructures and magnetite Fe3O4 at the surface after irradiation. |
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Corporate Author |
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Place of Publication |
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Wos |
000449125600004 |
Publication Date |
2018-08-18 |
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 |
0968-4328 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.98 |
Times cited |
9 |
Open Access |
Not_Open_Access: Available from 19.08.2020
|
Notes |
The authors wish to thank Valérie Lalanne for the sample preparation for TEM and Stijn Van den Broeck for the FIB cut elaboration. The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement 312483 – ESTEEM2 (Integrated Infrastructure Initiative–I3). |
Approved |
Most recent IF: 1.98 |
Call Number |
EMAT @ emat @c:irua:154356UA @ admin @ c:irua:154356 |
Serial |
5056 |
Permanent link to this record |
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Author |
Müller-Caspary, K.; Grieb, T.; Müßener, J.; Gauquelin, N.; Hille, P.; Schörmann, J.; Verbeeck, J.; Van Aert, S.; Eickhoff, M.; Rosenauer, A. |
Title |
Electrical Polarization in AlN/GaN Nanodisks Measured by Momentum-Resolved 4D Scanning Transmission Electron Microscopy |
Type |
A1 Journal article |
Year |
2019 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
Volume |
122 |
Issue |
10 |
Pages |
106102 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
We report the mapping of polarization-induced internal electric fields in AlN/GaN nanowire heterostructures at unit cell resolution as a key for the correlation of optical and structural phenomena in semiconductor optoelectronics. Momentum-resolved aberration-corrected scanning transmission electron microscopy is employed as a new imaging mode that simultaneously provides four-dimensional data in real and reciprocal space. We demonstrate how internal mesoscale and atomic electric fields can be separated in an experiment, which is verified by comprehensive dynamical simulations of multiple electron scattering. A mean difference of 5.3 +- 1.5 MV/cm is found for the polarization-induced electric fields in AlN and GaN, being in accordance with dedicated simulations and photoluminescence measurements in previous publications. |
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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Wos |
000461067700007 |
Publication Date |
2019-03-11 |
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 |
0031-9007 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.462 |
Times cited |
26 |
Open Access |
OpenAccess |
Notes |
The authors gratefully acknowledge the help of Natalie Claes for analyzing the EDX data. K. M.-C. acknowledges funding from the Initiative and Network Fund of the Helmholtz Association within the Helmholtz Young Investigator Group moreSTEM under Contract No. VHNG- 1317 at Forschungszentrum Jülich in Germany. The direct electron detector (Medipix3, Quantum Detectors) was funded by the Hercules fund from the Flemish Government. N. G. and J. V. acknowledge funding from the Geconcentreerde Onderzoekacties project Solarpaint of the University of Antwerp. T. G. and A. R. acknowledge support from the Deutsche Forschungsgemeinschaft (Germany) under Contract No. RO2057/8-3. This work also received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (Contract No. 770887). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project funding (G.0368.15N).; Helmholtz Association, VH-NG-1317 ; Forschungszentrum Jülich; Flemish Government; Universiteit Antwerpen; Deutsche Forschungsgemeinschaft, RO2057/8-3 ; H2020 European Research Council, 770887 ; Fonds Wetenschappelijk Onderzoek, G.0368.15N ; |
Approved |
Most recent IF: 8.462 |
Call Number |
UA @ lucian @UA @ admin @ c:irua:158120 |
Serial |
5157 |
Permanent link to this record |
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Author |
Yin, C.; Krishnan, D.; Gauquelin, N.; Verbeeck, J.; Aarts, J. |
Title |
Controlling the interfacial conductance in LaAlO3/SrTiO3 in 90 degrees off-axis sputter deposition |
Type |
A1 Journal article |
Year |
2019 |
Publication |
Physical review materials |
Abbreviated Journal |
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Volume |
3 |
Issue |
3 |
Pages |
034002 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
We report on the fabrication of conducting interfaces between LaAlO3 and SrTiO3 by 90 degrees off-axis sputtering in an Ar atmosphere. At a growth pressure of 0.04 mbar the interface is metallic, with a carrier density of the order of 1 x 10(13) cm(-2) at 3 K. By increasing the growth pressure, we observe an increase of the out-of-plane lattice constants of the LaAlO3 films while the in-plane lattice constants do not change. Also, the low-temperature sheet resistance increases with increasing growth pressure, leading to an insulating interface when the growth pressure reaches 0.10 mbar. We attribute the structural variations to an increase of the La/Al ratio, which also explains the transition from metallic behavior to insulating behavior of the interfaces. Our research shows that the control which is furnished by the Ar pressure makes sputtering as versatile a process as pulsed laser deposition, and emphasizes the key role of the cation stoichiometry of LaAlO3 in the formation of the conducting interface. |
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Corporate Author |
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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 |
000461077100002 |
Publication Date |
2019-03-12 |
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 |
2475-9953 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.926 |
Times cited |
4 |
Open Access |
Not_Open_Access |
Notes |
; We thank Nikita Lebedev, Aymen Ben Hamida, and Prateek Kumar for useful discussions and Giordano Mattoni, Jun Wang, Vincent Joly, and Hozanna Miro for their technical assistance. We also thank Jean-Marc Triscone and his group for sharing their design of the sputtering system with us. This work is part of the FOM research programme DESCO with Project No. 149, which is (partly) financed by the Netherlands Organisation for Scientific Research (NWO). C.Y. is supported by China Scholarship Council (CSC) with Grant No. 201508110214. N.G., D.K., and J.V. acknowledge financial support from the GOA project “Solarpaint” of the University of Antwerp. ; |
Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:158547 |
Serial |
5243 |
Permanent link to this record |
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Author |
O'Donnell, D.; Hassan, S.; Du, Y.; Gauquelin, N.; Krishnan, D.; Verbeeck, J.; Fan, R.; Steadman, P.; Bencok, P.; Dobrynin, A.N. |
Title |
Etching induced formation of interfacial FeMn in IrMn/CoFe bilayers |
Type |
A1 Journal article |
Year |
2019 |
Publication |
Journal of physics: D: applied physics |
Abbreviated Journal |
J Phys D Appl Phys |
Volume |
52 |
Issue |
16 |
Pages |
165002 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
The effect of ion etching on exchange bias in IrMn3/Co70Fe30 bilayers is investigated. In spite of the reduction of saturation magnetization caused by the embedding of Tr from the capping layer into the Co70Fe30 layer during the etching process, the exchange bias in samples with the same thickness of the Co70Fe30 layer is reducing in proportion to the etching power. X-ray magnetic circular dichroism measurements revealed the emergence of an uncompensated Mn magnetization after etching, which is antiferromagnetically coupled to the ferromagnetic layer. This suggests etching induced formation of small interfacial FeMn regions which leads to the decrease of effective exchange coupling between ferromagnetic and antiferromagnetic layers. |
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Wos |
000458524800001 |
Publication Date |
2019-01-31 |
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Series Issue |
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Edition |
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ISSN |
0022-3727 |
ISBN |
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Additional Links |
UA library record; WoS full record |
Impact Factor |
2.588 |
Times cited |
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Open Access |
OpenAccess |
Notes |
; This work was supported by Seagate Technology (Ireland). Beamline I10, Diamond Light Source, is acknowledged for provided beamtime. ; |
Approved |
Most recent IF: 2.588 |
Call Number |
UA @ admin @ c:irua:157458 |
Serial |
5247 |
Permanent link to this record |
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Author |
Behera, B.C.; Jana, S.; Bhat, S.G.; Gauquelin, N.; Tripathy, G.; Kumar, P.S.A.; Samal, D. |
Title |
Evidence for exchange bias coupling at the perovskite/brownmillerite interface in spontaneously stabilized SrCoO3-\delta/SrCoO2.5 bilayers |
Type |
A1 Journal article |
Year |
2019 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
Volume |
99 |
Issue |
2 |
Pages |
024425 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Interface effect in complex oxide thin-film heterostructures lies at the vanguard of current research to design technologically relevant functionality and explore emergent physical phenomena. While most of the previous works focus on the perovskite/perovskite heterostructures, the study of perovskite/brownmillerite interfaces remains in its infancy. Here, we investigate spontaneously stabilized perovskite-ferromagnet (SrCoO3-delta)/brownmillerite-antiferromagnet (SrCoO2.5) bilayer with T-N > T-C and discover an unconventional interfacial magnetic exchange bias effect. From magnetometry investigations, it is rationalized that the observed effect stems from the interfacial ferromagnet/antiferromagnet coupling. The possibility for coupled ferromagnet/spin-glass interface engendering such effect is ruled out. Strikingly, a finite coercive field persists in the paramagnetic state of SrCoO3-delta,whereas the exchange bias field vanishes at T-C . We conjecture the observed effect to be due to the effective external quenched staggered field provided by the antiferromagnetic layer for the ferromagnetic spins at the interface. Our results not only unveil a paradigm to tailor the interfacial magnetic properties in oxide heterostructures without altering the cations at the interface, but also provide a purview to delve into the fundamental aspects of exchange bias in such unusual systems, paving a big step forward in thin-film magnetism. |
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Wos |
000456481900003 |
Publication Date |
2019-01-23 |
Series Editor |
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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 |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
2 |
Open Access |
OpenAccess |
Notes |
; We are grateful to Sachin Sarangi for his superb technical support during magnetic measurements. We thank Gopal Pradhan for fruitful discussion. We thank Zhicheng Zhong for reading the manuscript and for suggestions. We thank T. Som for extending laboratory facility. D.S. and B.C.B. acknowledge the financial support from Max-Planck Society through Max Planck Partner Group. S.G.B. acknowledges the INSPIRE Faculty Fellowship Programme (DSTO1899) for the financial support. ; |
Approved |
Most recent IF: 3.836 |
Call Number |
UA @ admin @ c:irua:157562 |
Serial |
5248 |
Permanent link to this record |