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Author | Dixon, E.; Hadermann, J.; Hayward, M.A. | ||||
Title | The synthesis and complex anion-vacancy ordered structure of La0.33Sr0.67MnO2.42 | Type | A1 Journal article | ||
Year | 2011 | Publication | Journal of solid state chemistry | Abbreviated Journal | J Solid State Chem |
Volume | 184 | Issue | 7 | Pages | 1791-1799 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | The low-temperature topotactic reduction of La0.33Sr0.67MnO3 with NaH results in the formation of La0.33Sr0.67MnO2.42. A combination of neutron powder and electron diffraction data show that La0.33Sr0.67MnO2.42 adopts a novel anion-vacancy ordered structure with a 6-layer OOTOOT' stacking sequence of the octahedral and tetrahedral layers (Pcmb, a=5.5804(1) Å, b=23.4104(7) Å, c=11.2441(3) Å). A significant concentration of anion vacancies at the anion site, which links neighbouring octahedral layers means that only 25% of the octahedral manganese coordination sites actually have 6-fold MnO6 coordination, the remainder being MnO5 square-based pyramidal sites. The chains of cooperatively twisted apex-linked MnO4 tetrahedra adopt an ordered -LRLR- arrangement within each tetrahedral layer. This is the first published example of a fully refined structure of this type which exhibits such intralayer ordering of the twisted tetrahedral chains. The rationale behind the contrasting structures of La0.33Sr0.67MnO2.42 and other previously reported reduced La1−xSrxMnO3−y phases is discussed. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | London | Editor | ||
Language | Wos | 000292718500032 | Publication Date | 2011-05-26 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0022-4596; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.299 | Times cited | 8 | Open Access | |
Notes | Approved | Most recent IF: 2.299; 2011 IF: 2.159 | |||
Call Number | UA @ lucian @ c:irua:90885 | Serial | 3600 | ||
Permanent link to this record | |||||
Author | Maignan, A.; Martin, C.; Singh, K.; Simon, C.; Lebedev, O.I.; Turner, S. | ||||
Title | From spin induced ferroelectricity to dipolar glasses : spinel chromites and mixed delafossites | Type | A1 Journal article | ||
Year | 2012 | Publication | Journal of solid state chemistry | Abbreviated Journal | J Solid State Chem |
Volume | 195 | Issue | Pages | 41-49 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Magnetoelectric multiferroics showing coupling between polarization and magnetic order are attracting much attention. For instance, they could be used in memory devices. Metal-transition oxides are provided several examples of inorganic magnetoelectric multiferroics. In the present short review, spinel and delafossite chromites are described. For the former, an electric polarization is evidenced in the ferrimagnetic state for ACr2O4 polycrystalline samples (A=Ni, Fe, Co). The presence of a JahnTeller cation such as Ni2+ at the A site is shown to yield larger polarization values. In the delafossites, substitution by V3+ at the Cr or Fe site in CuCrO2 (CuFeO2) suppresses the complex antiferromagnetic structure at the benefit of a spin glass state. The presence of cation disorder, probed by transmission electron microscopy, favors relaxor-like ferroelectricity. The results on the ferroelectricity of ferrimagnets and insulating spin glasses demonstrate that, in this research field, transition-metal oxides are worth to be studied. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | London | Editor | ||
Language | Wos | 000309783600006 | Publication Date | 2012-02-09 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0022-4596; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.299 | Times cited | 27 | Open Access | |
Notes | Fwo | Approved | Most recent IF: 2.299; 2012 IF: 2.040 | ||
Call Number | UA @ lucian @ c:irua:101219 | Serial | 1286 | ||
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Author | Retuerto, M.; Li, M.R.; Go, Y.B.; Ignatov, A.; Croft, M.; Ramanujachary, K.V.; Herber, R.H.; Nowik, I.; Hodges, J.P.; Dachraoui, W.; Hadermann, J.; Greenblatt, M.; | ||||
Title | High magnetic ordering temperature in the perovskites Sr4-xLaxFe3ReO12 (x=0.0, 1.0, 2.0) | Type | A1 Journal article | ||
Year | 2012 | Publication | Journal of solid state chemistry | Abbreviated Journal | J Solid State Chem |
Volume | 194 | Issue | Pages | 48-58 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | A series of perovskites Sr4−xLaxFe3ReO12 (x=0.0, 1.0, 2.0) has been prepared by wet chemistry methods. The structure analyses by powder X-ray and neutron diffraction and electron microscopy show that these compounds adopt simple perovskite structures without cation ordering over the B sites: tetragonal (I4/mcm) for x=0.0 and 1.0 and orthorhombic (Pbmn) for x=2.0. The oxidation states of the cations in the compound with x=0.0 appear to be Fe3+/4+ and Re7+ and decrease for both with La substitution as evidenced by X-ray absorption spectroscopy. All the compounds are antiferromagnetically ordered above room temperature, as demonstrated by Mössbauer spectroscopy and the magnetic structures, which were determined by powder neutron diffraction. The substitution of Sr by La strongly affects the magnetic properties with an increase of TN up to ∼750 K. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | London | Editor | ||
Language | Wos | 000308896400009 | Publication Date | 2012-07-02 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0022-4596; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.299 | Times cited | 9 | Open Access | |
Notes | Approved | Most recent IF: 2.299; 2012 IF: 2.040 | |||
Call Number | UA @ lucian @ c:irua:101220 | Serial | 1435 | ||
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Author | Frolov, D.D.; Kotovshchikov, Y.N.; Morozov, I.V.; Boltalin, A.I.; Fedorova, A.A.; Marikutsa, A.V.; Rumyantseva, M.N.; Gaskov, A.M.; Sadovskaya, E.M.; Abakumov, A.M. | ||||
Title | Oxygen exchange on nanocrystalline tin dioxide modified by palladium | Type | A1 Journal article | ||
Year | 2012 | Publication | Journal of solid state chemistry | Abbreviated Journal | J Solid State Chem |
Volume | 186 | Issue | Pages | 1-8 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Temperature-programmed oxygen isotopic exchange study was performed on nanocrystalline tin dioxide-based materials synthesized via sol-gel route and modified by palladium. Such materials are widely used as resistive gas sensors. The experiments were carried out in a flow-reactor up to complete isotopic substitution of oxygen. Substantial rates of isotopic exchange for SnO2 were observed from about 700 K. The distribution of isotopic molecules O-16(2). (OO)-O-16-O-18 and O-18(2) corresponds to simple dioxygen heteroexchange mechanism with single lattice oxygen atom. The modification of SnO2 by Pd introduced multiple heteroexchange mechanism with preliminary O-2 dissociation on the clusters surface. Spill-over of atomic oxygen from Pd to the surface of SnO2 and fast exchange with lattice oxygen result in more than 100% increase of apparent heteroexchange rate. The exchange on SnO2/Pd was shown to be a complex process involving partial deactivation of the catalytic centers at temperature higher than 750 K. (C) 2011 Elsevier Inc. All rights reserved. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | London | Editor | ||
Language | Wos | 000299801400001 | Publication Date | 2011-12-08 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0022-4596; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.299 | Times cited | 34 | Open Access | |
Notes | Approved | Most recent IF: 2.299; 2012 IF: 2.040 | |||
Call Number | UA @ lucian @ c:irua:96202 | Serial | 2546 | ||
Permanent link to this record | |||||
Author | Napolsky, P.S.; Drozhzhin, O.A.; Istomin, S.Y.; Kazakov, S.M.; Antipov, E.V.; Galeeva, A.V.; Gippius, A.A.; Svensson, G.; Abakumov, A.M.; Van Tendeloo, G. | ||||
Title | Structure and high-temperature properties of the (Sr,Ca,Y)(Co,Mn)O3-y perovskites – perspective cathode materials for IT-SOFC | Type | A1 Journal article | ||
Year | 2012 | Publication | Journal of solid state chemistry | Abbreviated Journal | J Solid State Chem |
Volume | 192 | Issue | Pages | 186-194 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Oxygen deficient perovskites Sr0.75Y0.25Co1-xMnxO3-y, x=0.5 and 0.75, were prepared by using the citrate route at 1373-1573 K for 48 h. The cubic Pm-3m perovskite structure for x=0.5 was confirmed by electron diffraction study and refined using neutron powder diffraction (NPD) data. For x=0.75, the superstructure corresponding to a=root 2 x a(per), b=2 x a(per), c=root 2 x a(per) (a(0)b(-)b(-) tilt system, space group Imma) was revealed by electron diffraction. The solid solution Sr0.75-xCaxY0.25Co0.25Mn0.75O3-y, 0.1 <= x <= 0.6 and compound Ca0.75Y0.25Mn0.85Co0.15O2.92 were prepared in air at 1573 K for 48 h. The crystal structure of Ca0.75Y0.25Mn0.85Co0.15O2.92 was refined using NPD data (S.G. Pnma, a=5.36595(4), b=7.5091(6), c=5.2992(4) angstrom, R-p=0.057, R-wp=0.056, chi(2)=4.26). High-temperature thermal expansion properties of the prepared compounds were studied in air using both dilatometry and high-temperature X-ray powder diffraction data (HTXRPD). They expanding non-linearly at 298-1073 K due to the loss of oxygen at high temperatures. Calculated average thermal expansion coefficients (TECs) for Sr0.75Y0.25Co1-xMnxO3-y, x=0.5, 0.75 and Ca0.75Y0.25Mn0.85Co0.15O2.92(1) are 15.5, 15.1, and 13.8 ppm K-1, respectively. Anisotropy of the thermal expansion along different unit cell axes was observed for Sr0.15Ca0.6Y0.25Co0.25Mn0.75O3-y, and Ca0.75Y0.25Mn0.85Co0.15O2.92. Conductivity of Sr0.75Y0.25Co1-xMnxO3-y, x=0.5 and 0.75 increases with the temperature reaching 110 S/cm for x=0.5 and 44 S/cm for x=0.75 at 1173 K. Samples of Sr0.75-xCaxY0.25Co0.25Mn0.75O3-y, 0.1 <= y <= 0.6 were found to be n-type conductors at room temperature with the similar temperature dependence of the conductivity and demonstrated the increase of the sigma value from similar to 1 to similar to 50 S/cm as the temperature increases from 300 to 1173 K. Their conductivity is described in terms of the small polaron charge transport with the activation energy (E-p) increasing from 340 to 430 meV with an increase of the calcium content from x=0 to x=0.6. (C) 2012 Elsevier Inc. All rights reserved. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | London | Editor | ||
Language | Wos | 000307028300030 | Publication Date | 2012-03-31 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0022-4596; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.299 | Times cited | 5 | Open Access | |
Notes | Approved | Most recent IF: 2.299; 2012 IF: 2.040 | |||
Call Number | UA @ lucian @ c:irua:101119 | Serial | 3279 | ||
Permanent link to this record | |||||
Author | He, Z.B.; Deng, G.; Tian, H.; Xu, Q.; Van Tendeloo, G. | ||||
Title | 90° Rotation of orbital stripes in bilayer manganite PrCa2Mn2O7 studied by in situ transmission electron microscopy | Type | A1 Journal article | ||
Year | 2013 | Publication | Journal of solid state chemistry | Abbreviated Journal | J Solid State Chem |
Volume | 200 | Issue | Pages | 287-293 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | We present an in situ transmission electron microscopy study on the half-doped bilayer manganite PrCa2Mn2O7 to reveal the rotation process of the orbital stripes. Between the reported initial and final ordering phases, we identified an intermediate state with two sets of satellite spots to bridge the 90° rotation of the orbital stripes. Furthermore, we determined that the rotation of the orbital stripes does not always occur. Some restricted conditions for the orbital rotation to occur were found and reasons are discussed. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | London | Editor | ||
Language | Wos | 000317158000043 | Publication Date | 2013-02-08 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0022-4596; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.299 | Times cited | 5 | Open Access | |
Notes | Countatoms | Approved | Most recent IF: 2.299; 2013 IF: 2.200 | ||
Call Number | UA @ lucian @ c:irua:106183 | Serial | 20 | ||
Permanent link to this record | |||||
Author | Li, M.R.; Retuerto, M.; Bok Go, Y.; Emge, T.J.; Croft, M.; Ignatov, A.; Ramanujachary, K.V.; Dachraoui, W.; Hadermann, J.; Tang, M.B.; Zhao, J.T.; Greenblatt, M.; | ||||
Title | Synthesis, crystal structure, and properties of KSbO3-type Bi3Mn1.9Te1.1O11 | Type | A1 Journal article | ||
Year | 2013 | Publication | Journal of solid state chemistry | Abbreviated Journal | J Solid State Chem |
Volume | 197 | Issue | Pages | 543-549 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Single crystals of Bi3Mn1.9Te1.1O11 were prepared from NaCl+KCl flux. This compound adopts KSbO3-type crystal structure as evidenced by electron and single crystal X-ray diffraction analysis. The three-dimensional channel structure is formed by corner-sharing octahedral (Mn0.63Te0.37)2O10 dimers and two identical (Bi1)4(Bi2)2 interpenetrating lattices. The intra-dimer Mn/TeMn/Te distances in Bi3Mn1.9Te1.1O11 are short and are consistent with weak metalmetal interactions. The mixed oxidation state of manganese and the edge-sharing octahedral features are confirmed by X-ray near edge absorption spectroscopy measurements, which indicate Bi3(MnIII1.1MnIV0.8)TeVI1.1O11 with 57.7% Mn3+ and 42.3% Mn4+. The partial substitution of Te for Mn perturbs long-range magnetic interactions, thereby destroying the ferromagnetic ordering found in Bi3Mn3O11 (TC=150 K). | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | London | Editor | ||
Language | Wos | 000312281000076 | Publication Date | 2012-07-25 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0022-4596; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.299 | Times cited | 13 | Open Access | |
Notes | Approved | Most recent IF: 2.299; 2013 IF: 2.200 | |||
Call Number | UA @ lucian @ c:irua:101779 | Serial | 3452 | ||
Permanent link to this record | |||||
Author | Batuk, M.; Batuk, D.; Abakumov, A.M.; Hadermann, J. | ||||
Title | Pb5Fe3TiO11Cl : a rare example of Ti(IV) in a square pyramidal oxygen coordination | Type | A1 Journal article | ||
Year | 2014 | Publication | Journal of solid state chemistry | Abbreviated Journal | J Solid State Chem |
Volume | 215 | Issue | Pages | 245-252 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | A new oxychloride Pb5Fe3TiO11Cl has been synthesized using the solid state method. Its crystal and magnetic structure was investigated in the 1.5550 K temperature range using electron diffraction, high angle annular dark field scanning transmission electron microscopy, atomic resolution energy dispersive X-ray spectroscopy, neutron and X-ray powder diffraction. At room temperature Pb5Fe3TiO11Cl crystallizes in the P4/mmm space group with the unit cell parameters a=3.91803(3) Å and c=19.3345(2) Å. Pb5Fe3TiO11Cl is a new n=4 member of the oxychloride perovskite-based homologous series An+1BnO3n−1Cl. The structure is built of truncated Pb3Fe3TiO11 quadruple perovskite blocks separated by CsCl-type Pb2Cl slabs. The perovskite blocks consist of two layers of (Fe,Ti)O6 octahedra sandwiched between two layers of (Fe,Ti)O5 square pyramids. The Ti4+ cations are preferentially located in the octahedral layers, however, the presence of a noticeable amount of Ti4+ in a five-fold coordination environment has been undoubtedly proven using neutron powder diffraction and atomic resolution compositional mapping. Pb5Fe3TiO11Cl is antiferromagnetically ordered below 450(10) K. The ordered Fe magnetic moments at 1.5 K are 4.06(4) μB and 3.86(5) μB on the octahedral and square-pyramidal sites, respectively. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | London | Editor | ||
Language | Wos | 000336891300037 | Publication Date | 2014-04-12 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0022-4596; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.299 | Times cited | 4 | Open Access | |
Notes | Fwo G.0184.09n. | Approved | Most recent IF: 2.299; 2014 IF: 2.133 | ||
Call Number | UA @ lucian @ c:irua:117066 | Serial | 3551 | ||
Permanent link to this record | |||||
Author | Battle, P.D.; Avdeev, M.; Hadermann, J. | ||||
Title | The interplay of microstructure and magnetism in La3Ni2SbO9 | Type | A1 Journal article | ||
Year | 2014 | Publication | Journal of solid state chemistry | Abbreviated Journal | J Solid State Chem |
Volume | 220 | Issue | Pages | 163-166 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | La3Ni2SbO9 adopts a perovskite-related structure in which the six-coordinate cation sites are occupied alternately by Ni2+ and a disordered arrangement of Ni2+/Sb5+. A polycrystalline sample has been studied by neutron diffraction in applied magnetic fields of 0 <= H/kOe <= 50 at 5 K. In 0 kOe, weak magnetic Bragg scattering consistent with the adoption of a G-type ferrimagnetic structure is observed; the ordered component of the magnetic moment was found to be 0.89(7) mu(B) per Ni2+ cation. This increased to 1.60(3) mu(B) in a field of 50 kOe. Transmission electron microscopy revealed variations in the Ni:Sb ratio across crystallites of the sample. It is proposed that these composition variations disrupt the magnetic superexchange interactions within the compound, leading to domain formation and a reduced average moment. The application of a magnetic field aligns the magnetisation vectors across the crystal and the average moment measured by neutron diffraction increases accordingly. The role played by variations in the local chemical composition in determining the magnetic properties invites comparison with the behaviour of relaxor ferroelectrics. (C) 2014 Elsevier Inc. All rights reserved. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | London | Editor | ||
Language | Wos | 000343346100024 | Publication Date | 2014-09-01 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0022-4596; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.299 | Times cited | 13 | Open Access | |
Notes | Approved | Most recent IF: 2.299; 2014 IF: 2.133 | |||
Call Number | UA @ lucian @ c:irua:121134 | Serial | 3588 | ||
Permanent link to this record | |||||
Author | Velazco, A.; Nord, M.; Béché, A.; Verbeeck, J. | ||||
Title | Evaluation of different rectangular scan strategies for STEM imaging | Type | A1 Journal article | ||
Year | 2020 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | Issue | Pages | 113021 | ||
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | STEM imaging is typically performed by raster scanning a focused electron probe over a sample. Here we investigate and compare three different scan patterns, making use of a programmable scan engine that allows to arbitrarily set the sequence of probe positions that are consecutively visited on the sample. We compare the typical raster scan with a so-called ‘snake’ pattern where the scan direction is reversed after each row and a novel Hilbert scan pattern that changes scan direction rapidly and provides an homogeneous treatment of both scan directions. We experimentally evaluate the imaging performance on a single crystal test sample by varying dwell time and evaluating behaviour with respect to sample drift. We demonstrate the ability of the Hilbert scan pattern to more faithfully represent the high frequency content of the image in the presence of sample drift. It is also shown that Hilbert scanning provides reduced bias when measuring lattice parameters from the obtained scanned images while maintaining similar precision in both scan directions which is especially important when e.g. performing strain analysis. Compared to raster scanning with flyback correction, both snake and Hilbert scanning benefit from dose reduction as only small probe movement steps occur. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000544042800007 | Publication Date | 2020-05-21 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | 13 | Open Access | OpenAccess |
Notes | A.V., A.B. and J.V. acknowledge funding through FWO project G093417N ('Compressed sensing enabling low dose imaging in transmission electron microscopy') from the Flanders Research Fund. M.N. received support for this work from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 838001. J.V acknowledges funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3. | Approved | Most recent IF: 2.2; 2020 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:169225 | Serial | 6369 | ||
Permanent link to this record | |||||
Author | Fatermans, J.; den Dekker, Aj.; Müller-Caspary, K.; Gauquelin, N.; Verbeeck, J.; Van Aert, S. | ||||
Title | Atom column detection from simultaneously acquired ABF and ADF STEM images | Type | A1 Journal article | ||
Year | 2020 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 219 | Issue | Pages | 113046 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab | ||||
Abstract | In electron microscopy, the maximum a posteriori (MAP) probability rule has been introduced as a tool to determine the most probable atomic structure from high-resolution annular dark-field (ADF) scanning transmission electron microscopy (STEM) images exhibiting low contrast-to-noise ratio (CNR). Besides ADF imaging, STEM can also be applied in the annular bright-field (ABF) regime. The ABF STEM mode allows to directly visualize light-element atomic columns in the presence of heavy columns. Typically, light-element nanomaterials are sensitive to the electron beam, limiting the incoming electron dose in order to avoid beam damage and leading to images exhibiting low CNR. Therefore, it is of interest to apply the MAP probability rule not only to ADF STEM images, but to ABF STEM images as well. In this work, the methodology of the MAP rule, which combines statistical parameter estimation theory and model-order selection, is extended to be applied to simultaneously acquired ABF and ADF STEM images. For this, an extension of the commonly used parametric models in STEM is proposed. Hereby, the effect of specimen tilt has been taken into account, since small tilts from the crystal zone axis affect, especially, ABF STEM intensities. Using simulations as well as experimental data, it is shown that the proposed methodology can be successfully used to detect light elements in the presence of heavy elements. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000594768500005 | Publication Date | 2020-06-01 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | 9 | Open Access | OpenAccess |
Notes | The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (No. W.O.010.16N, No. G.0368.15N, No. G.0502.18N, EOS 30489208). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 770887). The authors acknowledge funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 823717 – ESTEEM3. The direct electron detector (Medipix3, Quantum Detectors) was funded by the Hercules fund from the Flemish Government. K. M. C. acknowledges funding from the Initiative and Network Fund of the Helmholtz Association (Germany) under contract VH-NG-1317. The authors thank Mark Huijben from the University of Twente (Enschede, The Netherlands) for providing the LiMn2O4 sample used in section 4.2 of this study. N. G., J. V., and S. V. A. acknowledge funding from the University of Antwerp through the Concerted Research Actions (GOA) project Solarpaint and the TOP project. | Approved | Most recent IF: 2.2; 2020 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:169706 | Serial | 6373 | ||
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Author | Prabhakara, V.; Jannis, D.; Guzzinati, G.; Béché, A.; Bender, H.; Verbeeck, J. | ||||
Title | HAADF-STEM block-scanning strategy for local measurement of strain at the nanoscale | Type | A1 Journal article | ||
Year | 2020 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 219 | Issue | Pages | 113099 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Lattice strain measurement of nanoscale semiconductor devices is crucial for the semiconductor industry as strain substantially improves the electrical performance of transistors. High resolution scanning transmission electron microscopy (HR-STEM) imaging is an excellent tool that provides spatial resolution at the atomic scale and strain information by applying Geometric Phase Analysis or image fitting procedures. However, HR-STEM images regularly suffer from scanning distortions and sample drift during image acquisition. In this paper, we propose a new scanning strategy that drastically reduces artefacts due to drift and scanning distortion, along with extending the field of view. It consists of the acquisition of a series of independent small subimages containing an atomic resolution image of the local lattice. All subimages are then analysed individually for strain by fitting a nonlinear model to the lattice images. The method allows flexible tuning of spatial resolution and the field of view within the limits of the dynamic range of the scan engine while maintaining atomic resolution sampling within the subimages. The obtained experimental strain maps are quantitatively benchmarked against the Bessel diffraction technique. We demonstrate that the proposed scanning strategy approaches the performance of the diffraction technique while having the advantage that it does not require specialized diffraction cameras. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000594768500006 | Publication Date | 2020-09-01 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | 4 | Open Access | OpenAccess |
Notes | A.B. D.J. and J.V. acknowledge funding through FWO project G093417N ('Compressed sensing enabling low dose imaging in transmission electron microscopy') from the Flanders Research Fund. J.V acknowledges funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3. The Qu-Ant-EM microscope and the direct electron detector used in the diffraction experiments was partly funded by the Hercules fund from the Flemish Government. This project has received funding from the GOA project “Solarpaint” of the University of Antwerp. GG acknowledges support from a postdoctoral fellowship grant from the Fonds Wetenschappelijk Onderzoek – Vlaanderen (FWO). Special thanks to Dr. Thomas Nuytten, Prof. Dr. Wilfried Vandervorst, Dr. Paola Favia, Dr. Olivier Richard from IMEC, Leuven and Prof. Dr. Sara Bals from EMAT, Antwerp for their continuous support and collaboration with the project and to the IMEC processing group for the device fabrication. | Approved | Most recent IF: 2.2; 2020 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:172485 | Serial | 6404 | ||
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Author | De wael, A.; De Backer, A.; Van Aert, S. | ||||
Title | Hidden Markov model for atom-counting from sequential ADF STEM images: Methodology, possibilities and limitations | Type | A1 Journal article | ||
Year | 2020 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 219 | Issue | Pages | 113131 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | We present a quantitative method which allows us to reliably measure dynamic changes in the atomic structure of monatomic crystalline nanomaterials from a time series of atomic resolution annular dark field scanning transmission electron microscopy images. The approach is based on the so-called hidden Markov model and estimates the number of atoms in each atomic column of the nanomaterial in each frame of the time series. We discuss the origin of the improved performance for time series atom-counting as compared to the current state-of-the-art atom-counting procedures, and show that the so-called transition probabilities that describe the probability for an atomic column to lose or gain one or more atoms from frame to frame are particularly important. Using these transition probabilities, we show that the method can also be used to estimate the probability and cross section related to structural changes. Furthermore, we explore the possibilities for applying the method to time series recorded under variable environmental conditions. The method is shown to be promising for a reliable quantitative analysis of dynamic processes such as surface diffusion, adatom dynamics, beam effects, or in situ experiments. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000594770500003 | Publication Date | 2020-10-03 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | Open Access | OpenAccess | |
Notes | This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 770887 and No. 823717 ESTEEM3). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through grants to A.D.w. and A.D.B. and projects G.0502.18N and EOS 30489208. | Approved | Most recent IF: 2.2; 2020 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:172449 | Serial | 6417 | ||
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Author | Gorji, S.; Kashiwar, A.; Mantha, L.S.; Kruk, R.; Witte, R.; Marek, P.; Hahn, H.; Kübel, C.; Scherer, T. | ||||
Title | Nanowire facilitated transfer of sensitive TEM samples in a FIB | Type | A1 Journal article | ||
Year | 2020 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 219 | Issue | Pages | 113075 | |
Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
Abstract | We introduce a facile approach to transfer thin films and other mechanically sensitive TEM samples inside a FIB with minimal introduction of stress and bending. The method is making use of a pre-synthetized flexible freestanding Ag nanowire attached to the tip of a typical tungsten micromanipulator inside the FIB. The main advantages of this approach are the significantly reduced stress-induced bending during transfer and attachment of the TEM sample, the very short time required to attach and cut the nanowire, the operation at very low dose and ion current, and only using the e-beam for Pt deposition during the transfer of sensitive TEM samples. This results in a reduced sample preparation time and reduced exposure to the ion beam or e-beam for Pt deposition during the sample preparation and thus also reduced contamination and beam damage. The method was applied to a number of thin films and different TEM samples in order to illustrate the advantageous benefits of the concept. In particular, the technique has been successfully tested for the transfer of a thin film onto a MEMS heating chip for in situ TEM experiments. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | Publication Date | 2020-07-15 | ||
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record | |
Impact Factor | 2.2 | Times cited | Open Access | ||
Notes | Approved | Most recent IF: 2.2; 2020 IF: 2.843 | |||
Call Number | UA @ admin @ c:irua:183618 | Serial | 6871 | ||
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Author | Hofer, C.; Pennycook, T.J. | ||||
Title | Reliable phase quantification in focused probe electron ptychography of thin materials | Type | A1 Journal Article | ||
Year | 2023 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 254 | Issue | Pages | 113829 | |
Keywords | A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; | ||||
Abstract | Electron ptychography provides highly sensitive, dose efficient phase images which can be corrected for aberrations after the data has been acquired. This is crucial when very precise quantification is required, such as with sensitivity to charge transfer due to bonding. Drift can now be essentially eliminated as a major impediment to focused probe ptychography, which benefits from the availability of easily interpretable simultaneous Z-contrast imaging. However challenges have remained when quantifying the ptychographic phases of atomic sites. The phase response of a single atom has a negative halo which can cause atoms to reduce in phase when brought closer together. When unaccounted for, as in integrating methods of quantification, this effect can completely obscure the effects of charge transfer. Here we provide a new method of quantification that overcomes this challenge, at least for 2D materials, and is robust to experimental parameters such as noise, sample tilt. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 001071608700001 | Publication Date | 2023-08-18 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | Open Access | ||
Notes | FWO, G013122N ; Horizon 2020 Framework Programme; Horizon 2020; European Research Council, 802123-HDEM ; European Research Council; | Approved | Most recent IF: 2.2; 2023 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:200272 | Serial | 8987 | ||
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Author | De Backer, A.; Bals, S.; Van Aert, S. | ||||
Title | A decade of atom-counting in STEM: From the first results toward reliable 3D atomic models from a single projection | Type | A1 Journal article | ||
Year | 2023 | Publication | Ultramicroscopy | Abbreviated Journal | |
Volume | Issue | Pages | 113702 | ||
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Quantitative structure determination is needed in order to study and understand nanomaterials at the atomic scale. Materials characterisation resulting in precise structural information is a crucial point to understand the structure–property relation of materials. Counting the number of atoms and retrieving the 3D atomic structure of nanoparticles plays an important role here. In this paper, an overview will be given of the atom-counting methodology and its applications over the past decade. The procedure to count the number of atoms will be discussed in detail and it will be shown how the performance of the method can be further improved. Furthermore, advances toward mixed element nanostructures, 3D atomic modelling based on the atom-counting results, and quantifying the nanoparticle dynamics will be highlighted. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000953765800001 | Publication Date | 2023-02-10 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | 3 | Open Access | OpenAccess |
Notes | This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S. Van Aert, Grant 815128 REALNANO to S. Bals, and Grant 823717 ESTEEM3). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0267.18N, G.0502.18N, G.0346.21N, and EOS 30489208) and a postdoctoral grant to A. De Backer. S. Van Aert acknowledges funding from the University of Antwerp Research fund (BOF) . The authors also thank the colleagues who have contributed to this work over the years, including T. Altantzis, E. Arslan Irmak, K.J. Batenburg, E. Bladt, A. De wael, R. Erni, C. Faes, B. Goris, L. Jones, L.M. Liz-Marzán, I. Lobato, G.T. Martinez, P.D. Nellist, M.D. Rosell, A. Rosenauer, K.H.W. van den Bos, A. Varambhia, and Z. Zhang.; esteem3reported; esteem3JRA | Approved | Most recent IF: 2.2; 2023 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:195896 | Serial | 7236 | ||
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Author | Zhang, Z.; Lobato, I.; De Backer, A.; Van Aert, S.; Nellist, P. | ||||
Title | Fast generation of calculated ADF-EDX scattering cross-sections under channelling conditions | Type | A1 Journal article | ||
Year | 2023 | Publication | Ultramicroscopy | Abbreviated Journal | |
Volume | 246 | Issue | Pages | 113671 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Advanced materials often consist of multiple elements which are arranged in a complicated structure. Quantitative scanning transmission electron microscopy is useful to determine the composition and thickness of nanostructures at the atomic scale. However, significant difficulties remain to quantify mixed columns by comparing the resulting atomic resolution images and spectroscopy data with multislice simulations where dynamic scattering needs to be taken into account. The combination of the computationally intensive nature of these simulations and the enormous amount of possible mixed column configurations for a given composition indeed severely hamper the quantification process. To overcome these challenges, we here report the development of an incoherent non-linear method for the fast prediction of ADF-EDX scattering cross-sections of mixed columns under channelling conditions. We first explain the origin of the ADF and EDX incoherence from scattering physics suggesting a linear dependence between those two signals in the case of a high-angle ADF detector. Taking EDX as a perfect incoherent reference mode, we quantitatively examine the ADF longitudinal incoherence under different microscope conditions using multislice simulations. Based on incoherent imaging, the atomic lensing model previously developed for ADF is now expanded to EDX, which yields ADF-EDX scattering cross-section predictions in good agreement with multislice simulations for mixed columns in a core–shell nanoparticle and a high entropy alloy. The fast and accurate prediction of ADF-EDX scattering cross-sections opens up new opportunities to explore the wide range of ordering possibilities of heterogeneous materials with multiple elements. | ||||
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Corporate Author | Zezhong Zhang | Thesis | |||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000995063900001 | Publication Date | 2022-12-28 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | Open Access | OpenAccess | |
Notes | European Research Council 770887 PICOMETRICS; Fonds Wetenschappelijk Onderzoek No.G.0502.18N; Horizon 2020, 770887 ; Horizon 2020 Framework Programme; European Research Council, 823717 ESTEEM3 ; esteem3reported; esteem3JRa | Approved | Most recent IF: 2.2; 2023 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:195890 | Serial | 7251 | ||
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Author | Lobato, I.; De Backer, A.; Van Aert, S. | ||||
Title | Real-time simulations of ADF STEM probe position-integrated scattering cross-sections for single element fcc crystals in zone axis orientation using a densely connected neural network | Type | A1 Journal article | ||
Year | 2023 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 251 | Issue | Pages | 113769 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Quantification of annular dark field (ADF) scanning transmission electron microscopy (STEM) images in terms of composition or thickness often relies on probe-position integrated scattering cross sections (PPISCS). In order to compare experimental PPISCS with theoretically predicted ones, expensive simulations are needed for a given specimen, zone axis orientation, and a variety of microscope settings. The computation time of such simulations can be in the order of hours using a single GPU card. ADF STEM simulations can be efficiently parallelized using multiple GPUs, as the calculation of each pixel is independent of other pixels. However, most research groups do not have the necessary hardware, and, in the best-case scenario, the simulation time will only be reduced proportionally to the number of GPUs used. In this manuscript, we use a learning approach and present a densely connected neural network that is able to perform real-time ADF STEM PPISCS predictions as a function of atomic column thickness for most common face-centered cubic (fcc) crystals (i.e., Al, Cu, Pd, Ag, Pt, Au and Pb) along [100] and [111] zone axis orientations, root-mean-square displacements, and microscope parameters. The proposed architecture is parameter efficient and yields accurate predictions for the PPISCS values for a wide range of input parameters that are commonly used for aberration-corrected transmission electron microscopes. |
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 001011617200001 | Publication Date | 2023-06-01 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record | |
Impact Factor | 2.2 | Times cited | Open Access | OpenAccess | |
Notes | This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S. Van Aert). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G034621N and G0A7723N) and a postdoctoral grant to A. De Backer. S. Van Aert acknowledges funding from the University of Antwerp Research fund (BOF), Belgium. | Approved | Most recent IF: 2.2; 2023 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:197275 | Serial | 8812 | ||
Permanent link to this record | |||||
Author | Denisov, N.; Jannis, D.; Orekhov, A.; Müller-Caspary, K.; Verbeeck, J. | ||||
Title | Characterization of a Timepix detector for use in SEM acceleration voltage range | Type | A1 Journal article | ||
Year | 2023 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 253 | Issue | Pages | 113777 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Hybrid pixel direct electron detectors are gaining popularity in electron microscopy due to their excellent properties. Some commercial cameras based on this technology are relatively affordable which makes them attractive tools for experimentation especially in combination with an SEM setup. To support this, a detector characterization (Modulation Transfer Function, Detective Quantum Efficiency) of an Advacam Minipix and Advacam Advapix detector in the 15–30 keV range was made. In the current work we present images of Point Spread Function, plots of MTF/DQE curves and values of DQE(0) for these detectors. At low beam currents, the silicon detector layer behaviour should be dominant, which could make these findings transferable to any other available detector based on either Medipix2, Timepix or Timepix3 provided the same detector layer is used. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 001026912700001 | Publication Date | 2023-06-08 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record | |
Impact Factor | 2.2 | Times cited | Open Access | OpenAccess | |
Notes | The authors acknowledge the financial support of the Research Foundation Flanders (FWO, Belgium) project SBO S000121N. The authors are grateful to Dr. Lobato for productive discussion of methods. | Approved | Most recent IF: 2.2; 2023 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:198258 | Serial | 8815 | ||
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Author | Van den Broek, W.; Jannis, D.; Verbeeck, J. | ||||
Title | Convexity constraints on linear background models for electron energy-loss spectra | Type | A1 Journal Article | ||
Year | 2023 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 254 | Issue | Pages | 113830 | |
Keywords | A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; | ||||
Abstract | In this paper convexity constraints are derived for a background model of electron energy loss spectra (EELS) that is linear in the fitting parameters. The model outperforms a power-law both on experimental and simulated backgrounds, especially for wide energy ranges, and thus improves elemental quantification results. Owing to the model’s linearity, the constraints can be imposed through fitting by quadratic programming. This has important advantages over conventional nonlinear power-law fitting such as high speed and a guaranteed unique solution without need for initial parameters. As such, the need for user input is significantly reduced, which is essential for unsupervised treatment of large datasets. This is demonstrated on a demanding spectrum image of a semiconductor device sample with a high number of elements over a wide energy range. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | Publication Date | 2023-08-15 | ||
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record | |
Impact Factor | 2.2 | Times cited | Open Access | Not_Open_Access | |
Notes | ECSEL, 875999 ; Horizon 2020; Horizon 2020 Framework Programme; Electronic Components and Systems for European Leadership; | Approved | Most recent IF: 2.2; 2023 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:200588 | Serial | 8961 | ||
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Author | Hofer, C.; Gao, C.; Chennit, T.; Yuan, B.; Pennycook, T.J. | ||||
Title | Phase offset method of ptychographic contrast reversal correction | Type | A1 Journal article | ||
Year | 2024 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | Issue | Pages | 113922 | ||
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | |||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 001164447000001 | Publication Date | 2024-01-08 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record | |
Impact Factor | 2.2 | Times cited | Open Access | Not_Open_Access | |
Notes | FWO, G013122N ; Horizon 2020 Framework Programme; European Research Council, 802123-HDEM ; European Research Council; | Approved | Most recent IF: 2.2; 2024 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:202379 | Serial | 8988 | ||
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Author | Şentürk, DG.; Yu, CP.; De Backer, A.; Van Aert, S. | ||||
Title | Atom counting from a combination of two ADF STEM images | Type | A1 Journal article | ||
Year | 2024 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 255 | Issue | Pages | 113859 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | To understand the structure–property relationship of nanostructures, reliably quantifying parameters, such as the number of atoms along the projection direction, is important. Advanced statistical methodologies have made it possible to count the number of atoms for monotype crystalline nanoparticles from a single ADF STEM image. Recent developments enable one to simultaneously acquire multiple ADF STEM images. Here, we present an extended statistics-based method for atom counting from a combination of multiple statistically independent ADF STEM images reconstructed from non-overlapping annular detector collection regions which improves the accuracy and allows one to retrieve precise atom-counts, especially for images acquired with low electron doses and multiple element structures. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 001089064200001 | Publication Date | 2023-09-23 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | Open Access | OpenAccess | |
Notes | This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S. Van Aert). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G034621N, G0A7723N, and EOS 40007495) and a postdoctoral grant to A. De Backer. S. Van Aert acknowledges funding from the University of Antwerp Research fund (BOF). | Approved | Most recent IF: 2.2; 2024 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:201008 | Serial | 8964 | ||
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Author | Şentürk, D.G.; De Backer, A.; Van Aert, S. | ||||
Title | Element specific atom counting for heterogeneous nanostructures: Combining multiple ADF STEM images for simultaneous thickness and composition determination | Type | A1 Journal Article | ||
Year | 2024 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 259 | Issue | Pages | 113941 | |
Keywords | A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; | ||||
Abstract | In this paper, a methodology is presented to count the number of atoms in heterogeneous nanoparticles based on the combination of multiple annular dark field scanning transmission electron microscopy (ADF STEM) images. The different non-overlapping annular detector collection regions are selected based on the principles of optimal statistical experiment design for the atom-counting problem. To count the number of atoms, the total intensities of scattered electrons for each atomic column, the so-called scattering cross-sections, are simultaneously compared with simulated library values for the different detector regions by minimising the squared differences. The performance of the method is evaluated for simulated Ni@Pt and Au@Ag core-shell nanoparticles. Our approach turns out to be a dose efficient alternative for the investigation of beam-sensitive heterogeneous materials as compared to the combination of ADF STEM and energy dispersive X-ray spectroscopy. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | Publication Date | 2024-02-19 | ||
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record | |
Impact Factor | 2.2 | Times cited | Open Access | OpenAccess | |
Notes | This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S. Van Aert). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0346.21N, GOA7723N, and EOS 40007495) and a postdoctoral grant to A. De Backer. S. Van Aert acknowledges funding from the University of Antwerp Research fund (BOF). | Approved | Most recent IF: 2.2; 2024 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:204353 | Serial | 8996 | ||
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Author | Gao, C.; Hofer, C.; Pennycook, T.J. | ||||
Title | On central focusing for contrast optimization in direct electron ptychography of thick samples | Type | A1 Journal article | ||
Year | 2024 | Publication | Ultramicroscopy | Abbreviated Journal | |
Volume | 256 | Issue | Pages | 113879-7 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Ptychography provides high dose efficiency images that can reveal light elements next to heavy atoms. However, despite ptychography having an otherwise single signed contrast transfer function, contrast reversals can occur when the projected potential becomes strong for both direct and iterative inversion ptychography methods. It has recently been shown that these reversals can often be counteracted in direct ptychography methods by adapting the focus. Here we provide an explanation of why the best contrast is often found with the probe focused to the middle of the sample. The phase contribution due to defocus at each sample slice above and below the central plane in this configuration effectively cancels out, which can prevent contrast reversals when dynamical scattering effects are not overly strong. In addition we show that the convergence angle can be an important consideration for removal of contrast reversals in relatively thin samples. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 001112166400001 | Publication Date | 2023-11-03 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | Open Access | Not_Open_Access | |
Notes | Approved | Most recent IF: 2.2; 2024 IF: 2.843 | |||
Call Number | UA @ admin @ c:irua:202029 | Serial | 9066 | ||
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Author | Prabhakara, V.; Jannis, D.; Béché, A.; Bender, H.; Verbeeck, J. | ||||
Title | Strain measurement in semiconductor FinFET devices using a novel moiré demodulation technique | Type | A1 Journal article | ||
Year | 2019 | Publication | Semiconductor science and technology | Abbreviated Journal | Semicond Sci Tech |
Volume | Issue | Pages | |||
Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
Abstract | Moiré fringes are used throughout a wide variety of applications in physics and engineering to bring out small variations in an underlying lattice by comparing with another reference lattice. This method was recently demonstrated in Scanning Transmission Electron Microscopy imaging to provide local strain measurement in crystals by comparing the crystal lattice with the scanning raster that then serves as the reference. The images obtained in this way contain a beating fringe pattern with a local period that represents the deviation of the lattice from the reference. In order to obtain the actual strain value, a region containing a full period of the fringe is required, which results in a compromise between strain sensitivity and spatial resolution. In this paper we propose an advanced setup making use of an optimised scanning pattern and a novel phase stepping demodulation scheme. We demonstrate the novel method on a series of 16 nm Si-Ge semiconductor FinFET devices in which strain plays a crucial role in modulating the charge carrier mobility. The obtained results are compared with both Nano-beam diffraction and the recently proposed Bessel beam diffraction technique. The setup provides a much improved spatial resolution over conventional moiré imaging in STEM while at the same time being fast and requiring no specialised diffraction camera as opposed to the diffraction techniques we compare to. |
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000537721200002 | Publication Date | 2019-11-29 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0268-1242 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.305 | Times cited | 8 | Open Access | |
Notes | The Qu-Ant-EM microscope and the direct electron detector used in the diffraction experiments was partly funded by the Hercules fund from the Flemish Government. This project has received funding from the GOA project “Solarpaint” of the University of Antwerp. We would also like to thank Dr. Thomas Nuytten and Prof. Dr. Wilfried Vandervorst from IMEC, Leuven for their continuous support and collaboration with the project. | Approved | Most recent IF: 2.305 | ||
Call Number | EMAT @ emat @c:irua:165794 | Serial | 5445 | ||
Permanent link to this record | |||||
Author | Denneulin, T.; Rouvière, J.L.; Béché, A.; Py, M.; Barnes, J.P.; Rochat, N.; Hartmann, J.M.; Cooper, D. | ||||
Title | The reduction of the substitutional C content in annealed Si/SiGeC superlattices studied by dark-field electron holography | Type | A1 Journal article | ||
Year | 2011 | Publication | Semiconductor science and technology | Abbreviated Journal | Semicond Sci Tech |
Volume | 26 | Issue | 12 | Pages | 1-10 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Si/Si(1 − x − y)GexCy superlattices are used in the construction of new microelectronic architectures such as multichannel transistors. The introduction of carbon in SiGe allows for compensation of the strain and to avoid plastic relaxation. However, the formation of incoherent β-SiC clusters during annealing limits the processability of SiGeC. This precipitation leads to a modification of the strain in the alloy due to the reduction of the substitutional carbon content. Here, we investigated the strain in annealed Si/Si0.744Ge0.244C0.012 superlattices grown by reduced pressure chemical vapour deposition using dark-field electron holography. The variation of the substitutional C content was calculated by correlating the results with finite-element simulations. The obtained values were then compared with Fourier-transformed infrared spectrometry measurements. It was shown that after annealing for 2 min at 1050 °C carbon no longer has any influence on strain in the superlattice, which behaves like pure SiGe. However, a significant proportion of substitutional C atoms remain in a third-nearest neighbour (3nn) configuration. It was deduced that the influence of 3nn C on strain is negligible and that only isolated atoms have a significant contribution. It was also proposed that the 3nn configuration is an intermediary step during the formation of SiC clusters. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | London | Editor | ||
Language | Wos | 000300151300010 | Publication Date | 2011-11-07 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0268-1242 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.305 | Times cited | Open Access | ||
Notes | Approved | Most recent IF: 2.305; 2011 IF: 1.723 | |||
Call Number | UA @ lucian @ c:irua:136427 | Serial | 4508 | ||
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Author | Ercolani, G.; Gorle, C.; Garcia Sánchez, C.; Corbari, C.; Mancini, M. | ||||
Title | RAMS and WRF sensitivity to grid spacing in large-eddy simulations of the dry convective boundary layer | Type | A1 Journal article | ||
Year | 2015 | Publication | Computers and fluids | Abbreviated Journal | Comput Fluids |
Volume | 123 | Issue | 123 | Pages | 54-71 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Large-eddy simulations (LESS) are frequently used to model the planetary boundary layer, and the choice of the grid cell size, numerical schemes and sub grid model can significantly influence the simulation results. In the present paper the impact of grid spacing on LES of an idealized atmospheric convective boundary layer (CBL), for which the statistics and flow structures are well understood, is assessed for two mesoscale models: the Regional Atmospheric Modeling System (RAMS) and the Weather Research and Forecasting model (WRF). Nine simulations are performed on a fixed computational domain (6 x 6 x 2 km), combining three different horizontal (120, 60, 30 m) and vertical (20, 10, 5 m) spacings. The impact of the cell size on the CBL is investigated by comparing turbulence statistics and velocity spectra. The results demonstrate that both WRF and RAMS can perform LES of the CBL under consideration without requiring extremely high computational loads, but they also indicate the importance of adopting a computational grid that is adequate for the numerical schemes and subgrid models used. In both RAMS and WRF a horizontal cell size of 30 m is required to obtain a suitable turbulence reproduction throughout the CBL height. Considering the vertical grid spacing, WRF produced similar results for all the three tested values, while in RAMS it should be ensured that the aspect ratio of the cells does not exceed a value of 3. The two models were found to behave differently in function of the grid resolution, and they have different shortcomings in their prediction of CBL turbulence. WRF exhibits enhanced damping at the smallest scales, while RAMS is prone to the appearance of spurious fluctuations in the flow when the grid aspect ratio is too high. (C) 2015 Elsevier Ltd. All rights reserved. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Oxford | Editor | ||
Language | Wos | 000365367500006 | Publication Date | 2015-10-08 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0045-7930 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.313 | Times cited | 3 | Open Access | |
Notes | Approved | Most recent IF: 2.313; 2015 IF: 1.619 | |||
Call Number | UA @ lucian @ c:irua:130200 | Serial | 4236 | ||
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Author | Chen, Z.; Tan, Z.; Ji, G.; Schryvers, D.; Ouyang, Q.; Li, Z. | ||||
Title | Effect of interface evolution on thermal conductivity of vacuum hot pressed SiC/Al composites | Type | A1 Journal article | ||
Year | 2015 | Publication | Advanced engineering materials | Abbreviated Journal | Adv Eng Mater |
Volume | 17 | Issue | 17 | Pages | 1076-1084 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | The SiC/Al composites have been fabricated by a vacuum hot pressing (VHP) process in order to study the effect of interface evolution on the global thermal conductivity (TC). By optimizing the VHP parameters of sintering temperature and time, the three different kinds of SiC/Al interface configurations, that is, non-bonded, diffusion-bonded, and reaction-bonded interfaces, are formed and identified by measurement of relative density, X-ray diffraction, scanning and (high-resolution) transmission electron microscopy. The VHPed composite sintered at 655 °C for 60 min is fully dense and presents a tightly-adhered and clean SiC/Al interface at the nanoscale, the ideal diffusion-bonded interface being the most favorable for minimizing interfacial thermal resistance, which in turn results in the highest TC of around 270 W/mK. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Weinheim | Editor | ||
Language | Wos | 000357680700019 | Publication Date | 2015-01-02 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1438-1656; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.319 | Times cited | 9 | Open Access | |
Notes | Approved | Most recent IF: 2.319; 2015 IF: 1.758 | |||
Call Number | c:irua:123000 | Serial | 818 | ||
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Author | Potapov, P.L.; Tirry, W.; Schryvers, D.; Sivel, V.G.M.; Wu, M.-Y.; Aslanidis, D.; Zandbergen, H. | ||||
Title | Cross-section transmission electron microscopy characterization of the near-surface structure of medical Nitinol superelastic tubing | Type | A1 Journal article | ||
Year | 2007 | Publication | Journal of materials science: materials in medicine | Abbreviated Journal | J Mater Sci-Mater M |
Volume | 18 | Issue | 3 | Pages | 483-492 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | |||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | London | Editor | ||
Language | Wos | 000244689700009 | Publication Date | 2007-02-27 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0957-4530;1573-4838; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.325 | Times cited | 14 | Open Access | |
Notes | Gao; Fwo | Approved | Most recent IF: 2.325; 2007 IF: 1.581 | ||
Call Number | UA @ lucian @ c:irua:63484 | Serial | 547 | ||
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Author | Pardo, J.A.; Santiso, J.; Solis, C.; Garcia, G.; Figueras, A.; Rossell, M.D. | ||||
Title | Thickness-dependent transport properties of Sr4Fe6O13 epitaxial thin films | Type | A1 Journal article | ||
Year | 2006 | Publication | Solid state ionics | Abbreviated Journal | Solid State Ionics |
Volume | 177 | Issue | 5/6 | Pages | 423-428 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | |||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000236301000001 | Publication Date | 2006-01-24 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0167-2738 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.354 | Times cited | Open Access | ||
Notes | Approved | Most recent IF: 2.354; 2006 IF: 2.190 | |||
Call Number | UA @ lucian @ c:irua:58049 | Serial | 4512 | ||
Permanent link to this record |