| |
Records |
Links |
|
Author |
Ranjbar, S.; Hadipour, A.; Vermang, B.; Batuk, M.; Hadermann, J.; Garud, S.; Sahayaraj, S.; Meuris, M.; Brammertz, G.; da Cunha, A.F.; Poortmans, J. |
|
| |
Title |
P-N Junction Passivation in Kesterite Solar Cells by Use of Solution-Processed TiO2 Layer |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
IEEE journal of photovoltaics |
Abbreviated Journal |
Ieee J Photovolt |
|
| |
Volume |
7 |
Issue |
7 |
Pages |
1130-1135 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
In this work, we used a solution-processed TiO2 layer between Cu2ZnSnSe4 and CdS buffer layer to reduce the recombination at the p–n junction. Introducing the TiO2 layer showed a positive impact on VOC but fill factor and efficiency decreased. Using a KCN treatment, we could create openings in the TiO2 layer, as confirmed by transmission electron microscopy measurements. Formation of these openings in the TiO2 layer led to the improvement of the short-circuit current, fill factor, and the efficiency of the modified solar cells. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000404258900026 |
Publication Date |
2017-04-25 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2156-3381 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.712 |
Times cited |
2 |
Open Access |
OpenAccess |
|
| |
Notes |
This work was supported in part by the European Union’s Horizon 2020 research and innovation program under Grant 640868, in part by the Flemish government, Department Economy, Science and Innovation, in part by the FEDER funds through the COMPETE 2020 Programme, and in part by the National Funds through FCT – Portuguese Foundation for Science and Technology under the project UID/CTM/50025/2013. The work of S. Ranjbar was supported by the Portuguese Science and Technology Foundation through Ph.D. grant SFRH/BD/78409/2011. The work of B. Vermang was supported by the Flemish Research Foundation FWO (mandate 12O4215N). |
Approved  |
Most recent IF: 3.712 |
|
| |
Call Number |
EMAT @ emat @ c:irua:143986 |
Serial |
4583 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Juchtmans, R.; Béché, A.; Abakumov, A.; Batuk, M.; Verbeeck, J. |
|
| |
Title |
Using electron vortex beams to determine chirality of crystals in transmission electron microscopy |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
91 |
Issue |
91 |
Pages |
094112 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
We investigate electron vortex beams elastically scattered on chiral crystals. After deriving a general expression for the scattering amplitude of a vortex electron, we study its diffraction on point scatterers arranged on a helix. We derive a relation between the handedness of the helix and the topological charge of the electron vortex on one hand and the symmetry of the higher-order Laue zones in the diffraction pattern on the other for kinematically and dynamically scattered electrons. We then extend this to atoms arranged on a helix as found in crystals which belong to chiral space groups and propose a method to determine the handedness of such crystals by looking at the symmetry of the diffraction pattern. In contrast to alternative methods, our technique does not require multiple scattering, which makes it possible to also investigate extremely thin samples in which multiple scattering is suppressed. In order to verify the model, elastic scattering simulations are performed, and an experimental demonstration on Mn2Sb2O7 is given in which we find the sample to belong to the right-handed variant of its enantiomorphic pair. This demonstrates the usefulness of electron vortex beams to reveal the chirality of crystals in a transmission electron microscope and provides the required theoretical basis for further developments in this field. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000352017000002 |
Publication Date |
2015-03-27 |
|
| |
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 |
54 |
Open Access |
|
|
| |
Notes |
Fwo; 312483 Esteem2; 278510 Vortex; esteem2jra1; esteem2jra2 ECASJO_; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
|
| |
Call Number |
c:irua:125512 c:irua:125512 |
Serial |
3825 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Mallick, S.; Zhang, W.; Batuk, M.; Gibbs, A.S.; Hadermann, J.; Halasyamani, P.S.; Hayward, M.A. |
|
| |
Title |
The crystal and defect structures of polar KBiNb2O7 |
Type |
A1 Journal article |
| |
Year |
2022 |
Publication |
Journal of the Chemical Society : Dalton transactions |
Abbreviated Journal |
Dalton T |
|
| |
Volume |
51 |
Issue |
5 |
Pages |
1866-1873 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
KBiNb2O7 was prepared from RbBiNb2O7 by a sequence of cation exchange reactions which first convert RbBiNb2O7 to LiBiNb2O7, before KBiNb2O7 is formed by a further K-for-Li cation exchange. A combination of neutron, synchrotron X-ray and electron diffraction data reveal that KBiNb2O7 adopts a polar, layered, perovskite structure (space group A11m) in which the BiNb2O7 layers are stacked in a (0, ½, z) arrangement, with the K+ cations located in half of the available 10-coordinate interlayer cation sites. The inversion symmetry of the phase is broken by a large displacement of the Bi3+ cations parallel to the y-axis. HAADF-STEM images reveal that KBiNb2O7 exhibits frequent stacking faults which convert the (0. ½, z) layer stacking to (½, 0, z) stacking and vice versa, essentially switching the x- and y-axes of the material. By fitting the complex diffraction peak shape of the SXRD data collected from KBiNb2O7 it is estimated that each layer has approximately an ~11% chance of being defective – a high level which is attributed to the lack of cooperative NbO6 tilting in the material, which limits the lattice strain associated with each fault. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000741540300001 |
Publication Date |
2022-01-05 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1477-9226 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
|
| |
Impact Factor |
4 |
Times cited |
|
Open Access |
OpenAccess |
|
| |
Notes |
Experiments at the Diamond Light Source were performed as part of the Block Allocation Group award “Oxford/Warwick Solid State Chemistry BAG to probe composition-structure-property relationships in solids” (EE18786). Experiments at the ISIS pulsed neutron facility were supported by a beam time allocation from the STFC (RB 2000148). SM thanks Somerville College for an Oxford Ryniker Lloyd scholarship. PSH and WZ thank the National Science Foundation (DMR-2002319) for support. |
Approved |
Most recent IF: 4 |
|
| |
Call Number |
EMAT @ emat @c:irua:185504 |
Serial |
6951 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Tyablikov, O.A.; Batuk, D.; Tsirlin, A.A.; Batuk, M.; Verchenko, V.Y.; Filimonov, D.S.; Pokholok, K.V.; Sheptyakov, D.V.; Rozova, M.G.; Hadermann, J.; Antipov, E.V.; Abakumov, A.M.; |
|
| |
Title |
{110}-Layered B-cation ordering in the anion-deficient perovskite Pb2.4Ba2.6Fe2Sc2TiO13 with the crystallographic shear structure |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
Journal of the Chemical Society : Dalton transactions |
Abbreviated Journal |
Dalton T |
|
| |
Volume |
44 |
Issue |
44 |
Pages |
10753-10762 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
A novel anion-deficient perovskite-based compound, Pb2.4Ba2.6Fe2Sc2TiO13, was synthesized via the citrate-based route. This compound is an n = 5 member of the A(n)B(n)O(3n-2) homologous series with unit-cell parameters related to the perovskite subcell a(p) approximate to 4.0 angstrom as a(p)root 2 x a(p) x 5a(p)root 2. The crystal structure of Pb2.4Ba2.6Fe2Sc2TiO13 consists of quasi-2D perovskite blocks with a thickness of three octahedral layers separated by the 1/2[110]((1) over bar 01)(p) crystallographic shear (CS) planes, which are parallel to the {110} plane of the perovskite subcell. The CS planes transform the corner-sharing octahedra into chains of edge-sharing distorted tetragonal pyramids. Using a combination of neutron powder diffraction, Fe-57 Mossbauer spectroscopy and atomic resolution electron energy-loss spectroscopy we demonstrate that the B-cations in Pb2.4Ba2.6Fe2Sc2TiO13 are ordered along the {110} perovskite layers with Fe3+ in distorted tetragonal pyramids along the CS planes, Ti4+ preferentially in the central octahedra of the perovskite blocks and Sc3+ in the outer octahedra of the perovskite blocks. Magnetic susceptibility and Mossbauer spectroscopy indicate a broadened magnetic transition around T-N similar to 45 K and the onset of local magnetic fields at low temperatures. The magnetic order is probably reminiscent of that in other A(n)B(n)O(3n-2) homologues, where G-type AFM order within the perovskite blocks has been observed. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
London |
Editor |
|
|
| |
Language |
|
Wos |
000355701000026 |
Publication Date |
2015-01-26 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1477-9226;1477-9234; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.029 |
Times cited |
1 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 4.029; 2015 IF: 4.197 |
|
| |
Call Number |
c:irua:127001 |
Serial |
22 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Zhang, F.; Inokoshi, M.; Batuk, M.; Hadermann, J.; Naert, I.; Van Meerbeek, B.; Vleugels, J. |
|
| |
Title |
Strength, toughness and aging stability of highly-translucent Y-TZP ceramics for dental restorations |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
Dental Materials |
Abbreviated Journal |
Dent Mater |
|
| |
Volume |
32 |
Issue |
32 |
Pages |
e327-e337 |
|
| |
Keywords |
A1 Journal article; Electron Microscopy for Materials Science (EMAT); |
|
| |
Abstract |
OBJECTIVE: The aim was to evaluate the optical properties, mechanical properties and aging stability of yttria-stabilized zirconia with different compositions, highlighting the influence of the alumina addition, Y2O3 content and La2O3 doping on the translucency. METHODS: Five different Y-TZP zirconia powders (3 commercially available and 2 experimentally modified) were sintered under the same conditions and characterized by X-ray diffraction with Rietveld analysis and scanning electron microscopy (SEM). Translucency (n=6/group) was measured with a color meter, allowing to calculate the translucency parameter (TP) and the contrast ratio (CR). Mechanical properties were appraised with four-point bending strength (n=10), single edge V-notched beam (SEVNB) fracture toughness (n=8) and Vickers hardness (n=10). The aging stability was evaluated by measuring the tetragonal to monoclinic transformation (n=3) after accelerated hydrothermal aging in steam at 134 degrees C, and the transformation curves were fitted by the Mehl-Avrami-Johnson (MAJ) equation. Data were analyzed by one-way ANOVA, followed by Tukey's HSD test (alpha=0.05). RESULTS: Lowering the alumina content below 0.25wt.% avoided the formation of alumina particles and therefore increased the translucency of 3Y-TZP ceramics, but the hydrothermal aging stability was reduced. A higher yttria content (5mol%) introduced about 50% cubic zirconia phase and gave rise to the most translucent and aging-resistant Y-TZP ceramics, but the fracture toughness and strength were considerably sacrificed. 0.2mol% La2O3 doping of 3Y-TZP tailored the grain boundary chemistry and significantly improved the aging resistance and translucency. Although the translucency improvement by La2O3 doping was less effective than for introducing a substantial amount of cubic zirconia, this strategy was able to maintain the mechanical properties of typical 3Y-TZP ceramics. SIGNIFICANCE: Three different approaches were compared to improve the translucency of 3Y-TZP ceramics. |
|
| |
Address |
KU Leuven, Department of Materials Engineering, Kasteelpark Arenberg 44, Belgium |
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
English |
Wos |
000389516400003 |
Publication Date |
2016-10-06 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0109-5641 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.07 |
Times cited |
|
Open Access |
|
|
| |
Notes |
The authors acknowledge the Research Fund of KU Leu- ven under project 0T/10/052 and the Fund for Scientific Research Flanders (FWO-Vlaanderen) under grant G.0431.10N. F. Zhang thanks the Research Fund of KU Leuven for her post- doctoral fellowship (PDM/15/153). We thank M. Peumans for the translucency measurements. |
Approved |
Most recent IF: 4.07 |
|
| |
Call Number |
EMAT @ emat @ c:irua:136821 |
Serial |
4313 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Zhang, F.; Inokoshi, M.; Batuk, M.; Hadermann, J.; Naert, I.; Van Meerbeek, B.; Vleugels, J. |
|
| |
Title |
Strength, toughness and aging stability of highly-translucent Y-TZP ceramics for dental restorations |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
Dental materials |
Abbreviated Journal |
Dent Mater |
|
| |
Volume |
32 |
Issue |
12 |
Pages |
E327-E337 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Objective. The aim was to evaluate the optical properties, mechanical properties and aging stability of yttria-stabilized zirconia with different compositions, highlighting the influence of the alumina addition, Y2O3 content and La2O3 doping on the translucency. Methods. Five different Y-TZP zirconia powders (3 commercially available and 2 experimentally modified) were sintered under the same conditions and characterized by X-ray diffraction with Rietveld analysis and scanning electron microscopy (SEM). Translucency (n = 6/group) was measured with a color meter, allowing to calculate the translucency parameter (TP) and the contrast ratio (CR). Mechanical properties were appraised with four-point bending strength (n = 10), single edge V-notched beam (SEVNB) fracture toughness (n = 8) and Vickers hardness (n = 10). The aging stability was evaluated by measuring the tetragonal to monoclinic transformation (n = 3) after accelerated hydrothermal aging in steam at 134 degrees C, and the transformation curves were fitted by the Mehl-Avrami-Johnson (MAJ) equation. Data were analyzed by one-way ANOVA, followed by Tukey's HSD test (alpha = 0.05). Results. Lowering the alumina content below 0.25 wt.% avoided the formation of alumina particles and therefore increased the translucency of 3Y-TZP ceramics, but the hydrothermal aging stability was reduced. A higher yttria content (5 mol%) introduced about 50% cubic zirconia phase and gave rise to the most translucent and aging-resistant Y-TZP ceramics, but the fracture toughness and strength were considerably sacrificed. 0.2 mol% La2O3 doping of 3Y-TZP tailored the grain boundary chemistry and significantly improved the aging resistance and translucency. Although the translucency improvement by La2O3 doping was less effective than for introducing a substantial amount of cubic zirconia, this strategy was able to maintain the mechanical properties of typical 3Y-TZP ceramics. Significance. Three different approaches were compared to improve the translucency of 3YTZP ceramics. (C) 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Copenhagen |
Editor |
|
|
| |
Language |
|
Wos |
000389516400003 |
Publication Date |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0109-5641 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
|
| |
Impact Factor |
4.07 |
Times cited |
47 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 4.07 |
|
| |
Call Number |
UA @ lucian @ c:irua:140246 |
Serial |
4447 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Buffière, M.; Zaghi, A.E.; Lenaers, N.; Batuk, M.; Khelifi, S.; Drijkoningen, J.; Hamon, J.; Stesmans, A.; Kepa, J.; Afanas’ev, V.V.; Hadermann, J.; D’Haen, J.; Manca, J.; Vleugels, J.; Meuris, M.; Poortmans, J.; |
|
| |
Title |
Effect of binder content in Cu-In-Se precursor ink on the physical and electrical properties of printed CuInSe2 solar cells |
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 |
47 |
Pages |
27201-27209 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Printed chalcopyrite thin films have attracted considerable attention in recent years due to their potential in the high-throughput production of photovoltaic devices. To improve the homogeneity of printed CuInSe2 (CISe) layers, chemical additives such as binder can be added to the precursor ink. In this contribution, we investigate the influence of the dicyandiamide (DCDA) content, used as a binder in the precursor ink, on the physical and electrical properties of printed CISe solar cells. It is shown that the use of the binder leads to a dense absorber, composed of large CISe grains close to the surface, while the bulk of the layer consists of CISe crystallites embedded in a CuxS particle based matrix, resulting from the limited sintering of the precursor in this region. The expected additional carbon contamination of the CISe layer due to the addition of the binder appears to be limited, and the optical properties of the CISe layer are similar to the reference sample without additive. The electrical characterization of the corresponding CISe/CdS solar cells shows a degradation of the efficiency of the devices, due to a modification in the predominant recombination mechanisms and a limitation of the space charge region width when using the binder; both effects could be explained by the inhomogeneity of the bulk of the CISe absorber and high defect density at the CISe/CuxS-based matrix interface. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Washington, D.C. |
Editor |
|
|
| |
Language |
|
Wos |
000345722400003 |
Publication Date |
2014-11-06 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
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 |
4 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 4.536; 2014 IF: 4.772 |
|
| |
Call Number |
UA @ lucian @ c:irua:121332 |
Serial |
801 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Savina, A.A.; Saiutina, V.V.; Morozov, A.V.; Boev, A.O.; Aksyonov, D.A.; Dejoie, C.; Batuk, M.; Bals, S.; Hadermann, J.; Abakumov, A.M. |
|
| |
Title |
Chemistry, local molybdenum clustering, and electrochemistry in the Li2+xMo1-xO3 solid solutions |
Type |
A1 Journal article |
| |
Year |
2022 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
|
| |
Volume |
61 |
Issue |
14 |
Pages |
5637-5652 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
A broad range of cationic nonstoichiometry has been demonstratedfor the Li-rich layered rock-salt-type oxide Li2MoO3, which has generally been considered as a phase with a well-defined chemical composition. Li2+xMo1-xO3(-0.037 <= x <= 0.124) solid solutions were synthesized via hydrogen reduction ofLi2MoO4in the temperature range of 650-1100 degrees C, withxdecreasing with theincrease of the reduction temperature. The solid solutions adopt a monoclinicallydistorted O3-type layered average structure and demonstrate a robust localordering of the Li cations and Mo3triangular clusters within the mixed Li/Mocationic layers. The local structure was scrutinized in detail by electron diffractionand aberration-corrected scanning transmission electron microcopy (STEM),resulting in an ordering model comprising a uniform distribution of the Mo3clusters compatible with local electroneutrality and chemical composition. The geometry of the triangular clusters with their oxygenenvironment (Mo3O13groups) has been directly visualized using differential phase contrast STEM imaging. The established localstructure was used as input for density functional theory (DFT)-based calculations; they support the proposed atomic arrangementand provide a plausible explanation for the staircase galvanostatic charge profiles upon electrochemical Li+extraction fromLi2+xMo1-xO3in Li cells. According to DFT, all electrochemical capacity in Li2+xMo1-xO3solely originates from the cationic Moredox process, which proceeds via oxidation of the Mo3triangular clusters into bent Mo3chains where the electronic capacity of the clusters depends on the initial chemical composition and Mo oxidation state defining the width of the first charge low-voltageplateau. Further oxidation at the high-voltage plateau proceeds through decomposition of the Mo3chains into Mo2dimers and further into individual Mo6+cations |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000789034200023 |
Publication Date |
2022-04-01 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0020-1669 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.6 |
Times cited |
3 |
Open Access |
Not_Open_Access |
|
| |
Notes |
The authors acknowledge Russian Science Foundation (grant 20-43-01012) and Research Foundation Flanders (FWO Vlaanderen, project number G0F1320N) for financial support. The authors are grateful to AICF of Skoltech for providing access to electron microscopy equipment. The authors are grateful to Prof. G. Van Tendeloo for discussing the results. |
Approved |
Most recent IF: 4.6 |
|
| |
Call Number |
UA @ admin @ c:irua:188631 |
Serial |
7079 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Sheath, B.C.; Xu, X.; Manuel, P.; Hadermann, J.; Batuk, M.; O'Sullivan, J.; Bonilla, R.S.; Clarke, S.J. |
|
| |
Title |
Structures and magnetic ordering in layered Cr oxide arsenides Sr₂CrO₂Cr₂OAs₂ and Sr₂CrO₃CrAs |
Type |
A1 Journal article |
| |
Year |
2022 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
|
| |
Volume |
61 |
Issue |
31 |
Pages |
10-12385 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Two novel chromium oxide arsenide materials have been synthesized, Sr2CrO2Cr2OAs2 (i.e., Sr2Cr3As2O3) and Sr2CrO3CrAs (i.e., Sr2Cr2AsO3), both of which contain chromium ions in two distinct layers. Sr2CrO2Cr2OAs2 was targeted following electron microscopy measurements on a related phase. It crystallizes in the space group P4/mmm and accommodates distorted CrO4As2 octahedra containing Cr2+ and distorted CrO(2)As(4 )octahedra containing Cr3+. In contrast, Sr2CrO3CrAs incorporates Cr3+ in CrO5 square-pyramidal coordination in [Sr2CrO3](+) layers and Cr2+ ions in CrAs(4 )tetrahedra in [CrAs](-) layers and crystallizes in the space group P4/nmm. Powder neutron diffraction data reveal antiferromagnetic ordering in both compounds. In Sr2CrO3CrAs the Cr2+ moments in the [CrAs](-) layers exhibit long-range ordering, while the Cr3+ moments in the [Sr2CrO3](+) layers only exhibit short-range ordering. However, in Sr2CrO2Cr2OAs2, both the Cr(2+ )moments in the CrO4As2 environments and the Cr3+ moments in the CrO2As4 polyhedra are long-range-ordered below 530(10) K. Above this temperature, only the Cr3+ moments are ordered with a Neel temperature slightly in excess of 600 K. A subtle structural change is evident in Sr2CrO2Cr2OAs2 below the magnetic ordering transitions. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000841943600001 |
Publication Date |
2022-07-27 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0020-1669 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.6 |
Times cited |
|
Open Access |
OpenAccess |
|
| |
Notes |
|
Approved |
Most recent IF: 4.6 |
|
| |
Call Number |
UA @ admin @ c:irua:190007 |
Serial |
7215 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Xu, X.; Jones, M.A.; Cassidy, S.J.; Manuel, P.; Orlandi, F.; Batuk, M.; Hadermann, J.; Clarke, S.J. |
|
| |
Title |
Magnetic Ordering in the Layered Cr(II) Oxide Arsenides Sr2CrO2Cr2As2and Ba2CrO2Cr2As2 |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Inorganic Chemistry |
Abbreviated Journal |
Inorg Chem |
|
| |
Volume |
59 |
Issue |
21 |
Pages |
15898-15912 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Sr2CrO2Cr2As2 and Ba2CrO2Cr2As2 with Cr2+ ions in CrO2 sheets and in CrAs layers crystallize with the Sr2Mn3Sb2O2 structure (space group I4/mmm, Z = 2) and lattice parameters a = 4.00800(2) Å, c = 18.8214(1) Å (Sr2CrO2Cr2As2) and a = 4.05506(2) Å, c = 20.5637(1) Å (Ba2CrO2Cr2As2) at room temperature. Powder neutron diffraction reveals checkerboard-type antiferromagnetic ordering of the Cr2+ ions in the arsenide layers below TN1Sr, of 600(10) K (Sr2CrO2Cr2As2) and TN1Ba 465(5) K (Ba2CrO2Cr2As2) with the moments initially directed perpendicular to the layers in both compounds. Checkerboard-type antiferromagnetic ordering of the Cr2+ ions in the oxide layer below 230(5) K for Ba2CrO2Cr2As2 occurs with these moments also perpendicular to the layers, consistent with the orientation preferences of d4 moments in the two layers. In contrast, below 330(5) K in Sr2CrO2Cr2As2, the oxide layer Cr2+ moments are initially oriented in the CrO2 plane; but on further cooling, these moments rotate to become perpendicular to the CrO2 planes, while the moments in the arsenide layers rotate by 90° with the moments on the two sublattices remaining orthogonal throughout [behavior recently reported independently by Liu et al. [Liu et al. Phys. Rev. B 2018, 98, 134416]]. In Sr2CrO2Cr2As2, electron diffraction and high resolution powder X-ray diffraction data show no evidence for a structural distortion that would allow the two Cr2+ sublattices to couple, but high resolution neutron powder diffraction data suggest a small incommensurability between the magnetic structure and the crystal structure, which may account for the coupling of the two sublattices and the observed spin reorientation. The saturation values of the Cr2+ moments in the CrO2 layers (3.34(1) μB (for Sr2CrO2Cr2As2) and 3.30(1) μB (for Ba2CrO2Cr2As2)) are larger than those in the CrAs layers (2.68(1) μB for Sr2CrO2Cr2As2 and 2.298(8) μB for Ba2CrO2Cr2As2) reflecting greater covalency in the arsenide layers. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000588738100035 |
Publication Date |
2020-11-02 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0020-1669 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.6 |
Times cited |
|
Open Access |
OpenAccess |
|
| |
Notes |
We thank the UK EPSRC (EP/M020517/1 and EP/P018874/ 1) and the Leverhulme Trust (RPG-2014-221) for funding and the ISIS pulsed neutron and muon source (RB1610357 and RB1700075) and the Diamond Light Source Ltd. (EE13284 and EE18786) for the award of beam time. We thank Dr. A. Baker and Dr. C. Murray for support on I11. |
Approved |
Most recent IF: 4.6; 2020 IF: 4.857 |
|
| |
Call Number |
EMAT @ emat @c:irua:176058 |
Serial |
6704 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Gamon, J.; Bassat, J.-M.; Villesuzanne, A.; Duttine, M.; Batuk, M.; Vandemeulebroucke, D.; Hadermann, J.; Alassani, F.; Weill, F.; Durand, E.; Demourgues, A. |
|
| |
Title |
Impact of anionic ordering on the iron site distribution and valence states in oxyfluoride Sr2FeO3+xF1-x(x=0.08, 0.2) with a layered Perovskite network |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
|
|
| |
Volume |
62 |
Issue |
27 |
Pages |
10822-10832 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Sr2FeO3+x F1-x (x = 0.08, 0.2), an n = 1 Ruddlesden-Popperphase, was synthesized from the oxidationof Sr2FeO3F in air at high temperature followinga fluorine for oxygen substitution and Fe3+ to Fe4+ oxidation. A structural investigation of both compounds was performedusing complementary and high-resolution techniques (Synchrotron X-rayand electron diffraction, Mo''ssbauer spectroscopy, HR-STEM)coupled to DFT calculation. This study reveals that oxidation leadsto a high degree of apical anion disorder coupled to antiphase boundaries. Sr2FeO3F, an oxyfluoride compoundwith an n = 1 Ruddlesden-Popper structure,was identifiedas a potential interesting mixed ionic and electronic conductor (MIEC).The phase can be synthesized under a range of different pO(2) atmospheres, leading to various degrees of fluorinefor oxygen substitution and Fe4+ content. A structuralinvestigation and thorough comparison of both argon- and air-synthesizedcompounds were performed by combining high-resolution X-ray and electrondiffraction, high-resolution scanning transmission electron microscopy,Mo''ssbauer spectroscopy, and DFT calculations. While the argon-synthesizedphase shows a well-behaved O/F ordered structure, this study revealedthat oxidation leads to averaged large-scale anionic disorder on theapical site. In the more oxidized Sr2FeO3.2F0.8 oxyfluoride, containing 20% of Fe4+, two differentFe positions can be identified with a 32%/68% occupancy (P4/nmm space group). This originates due to the presenceof antiphase boundaries between ordered domains within the grains.Relations between site distortion and valence states as well as stabilityof apical anionic sites (O vs F) are discussed. This study paves theway for further studies on both ionic and electronic transport propertiesof Sr2FeO3.2F0.8 and its use in MIEC-baseddevices, such as solid oxide fuel cells. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
001018974700001 |
Publication Date |
2023-06-29 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0020-1669 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
|
| |
Impact Factor |
4.6 |
Times cited |
|
Open Access |
Not_Open_Access |
|
| |
Notes |
|
Approved |
Most recent IF: 4.6; 2023 IF: 4.857 |
|
| |
Call Number |
UA @ admin @ c:irua:197789 |
Serial |
8881 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Zhang, F.; Chevalier, J.; Olagnon, C.; Batuk, M.; Hadermann, J.; Van Meerbeek, B.; Vleugels, J. |
|
| |
Title |
Grain-boundary engineering for aging and slow-crack-growth resistant zirconia |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Journal of dental research |
Abbreviated Journal |
J Dent Res |
|
| |
Volume |
96 |
Issue |
7 |
Pages |
774-779 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Ceramic materials are prone to slow crack growth, resulting in strength degradation over time. Although yttria-stabilized zirconia (Y-TZP) ceramics have higher crack resistance than other dental ceramics, their aging susceptibility threatens their long-term performance in aqueous environments such as the oral cavity. Unfortunately, increasing the aging resistance of Y-TZP ceramics normally reduces their crack resistance. Our recently conducted systematic study of doping 3Y-TZP with various trivalent cations revealed that lanthanum oxide (La2O3) and aluminum oxide (Al2O3) have the most potent effect to retard the aging kinetics of 3Y-TZP. In this study, the crack-propagation behavior of La2O3 and Al2O3 co-doped 3Y-TZP ceramics was investigated by double-torsion methods. The grain boundaries were examined using scanning transmission electron microscopy and energy-dispersive spectroscopy (STEM-EDS). Correlating these analytic data with hydrothermal aging studies using different doping systems, a strategy to strongly bind the segregated dopant cations with the oxygen vacancies at the zirconia-grain boundary was found to improve effectively the aging resistance of Y-TZP ceramics without affecting the resistance to crack propagation. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
St. Louis, Mo. |
Editor |
|
|
| |
Language |
|
Wos |
000403934500010 |
Publication Date |
2017-03-10 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0022-0345 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.755 |
Times cited |
3 |
Open Access |
Not_Open_Access |
|
| |
Notes |
; This research was supported by the Research Fund of KU Leuven under project 0T/ 10/052 and the Research Foundation-Flanders (FWO-Vlaanderen) under grant G.0431.10N. We thank J.W. Seo for TEM and sample preparations. F. Zhang thanks the Research Fund of KU Leuven for her postdoctoral fellowship (PDM/15/153) and the JECS-Trust for the travel grant (No. 201599) to perform double-torsion testing in the MATEIS lab of INSA, Lyon, France. Jerome Chevalier would like to dedicate this paper to Maria Cattani Lorente, who recently passed away under tragic conditions. She was deeply involved in the study of dental zirconia and we will miss her. The authors declare no potential conflicts of interest with respect to the authorship and/or publication of this article. ; |
Approved |
Most recent IF: 4.755 |
|
| |
Call Number |
UA @ lucian @ c:irua:144161 |
Serial |
4660 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Khelifi, S.; Brammertz, G.; Choubrac, L.; Batuk, M.; Yang, S.; Meuris, M.; Barreau, N.; Hadermann, J.; Vrielinck, H.; Poelman, D.; Neyts, K.; Vermang, B.; Lauwaert, J. |
|
| |
Title |
The path towards efficient wide band gap thin-film kesterite solar cells with transparent back contact for viable tandem application |
Type |
A1 Journal article |
| |
Year |
2021 |
Publication |
Solar Energy Materials And Solar Cells |
Abbreviated Journal |
Sol Energ Mat Sol C |
|
| |
Volume |
219 |
Issue |
|
Pages |
110824 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Wide band gap thin-film kesterite solar cell based on non-toxic and earth-abundant materials might be a suitable candidate as a top cell for tandem configuration in combination with crystalline silicon as a bottom solar cell. For this purpose and based on parameters we have extracted from electrical and optical characterization techniques of Cu2ZnGeSe4 absorbers and solar cells, a model has been developed to describe the kesterite top cell efficiency limitations and to investigate the different possible configurations with transparent back contact for fourterminal tandem solar cell application. Furthermore, we have studied the tandem solar cell performance in view of the band gap and the transparency of the kesterite top cell and back contact engineering. Our detailed analysis shows that a kesterite top cell with efficiency > 14%, a band gap in the range of 1.5-1.7 eV and transparency above 80% at the sub-band gaps photons energies are required to achieve a tandem cell with higher efficiency than with a single silicon solar cell. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000591683500002 |
Publication Date |
2020-10-08 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0927-0248 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.784 |
Times cited |
|
Open Access |
OpenAccess |
|
| |
Notes |
The authors would like to acknowledge the SWInG project financed by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 640868 and the Research Foundation Flanders-Hercules Foundation (FWO-Vlaanderen, project No AUGE/13/16:FT-IMAGER). |
Approved |
Most recent IF: 4.784 |
|
| |
Call Number |
EMAT @ emat @c:irua:174337 |
Serial |
6706 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Cassidy, S.J.; Batuk, M.; Batuk, D.; Hadermann, J.; Woodruff, D.N.; Thompson, A.L.; Clarke, S.J. |
|
| |
Title |
Complex Microstructure and Magnetism in Polymorphic CaFeSeO |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
|
| |
Volume |
55 |
Issue |
55 |
Pages |
10714-10726 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
The structural complexity of the antiferromagnetic oxide selenide CaFeSeO is described. The compound contains puckered FeSeO layers composed of FeSe2O2 tetrahedra sharing all their vertexes. Two polymorphs coexist that can be derived from an archetype BaZnSO structure by cooperative tilting of the FeSe2O2 tetrahedra. The polymorphs differ in the relative arrangement of the puckered layers of vertex-linked FeSe2O2 tetrahedra. In a noncentrosymmetric Cmc21 polymorph (a = 3.89684(2) A, b = 13.22054(8) A, c = 5.93625(2) A) the layers are related by the C-centering translation, while in a centrosymmetric Pmcn polymorph, with a similar cell metric (a = 3.89557(6) A, b = 13.2237(6) A, c = 5.9363(3) A), the layers are related by inversion. The compound shows long-range antiferromagnetic order below a Neel temperature of 159(1) K with both polymorphs showing antiferromagnetic coupling via Fe-O-Fe linkages and ferromagnetic coupling via Fe-Se-Fe linkages within the FeSeO layers. The magnetic susceptibility also shows evidence for weak ferromagnetism which is modeled in the refinements of the magnetic structure as arising from an uncompensated spin canting in the noncentrosymmetric polymorph. There is also a spin glass component to the magnetism which likely arises from the disordered regions of the structure evident in the transmission electron microscopy. |
|
| |
Address |
Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QR, United Kingdom |
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
English |
Wos |
000385785700085 |
Publication Date |
2016-10-05 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0020-1669 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.857 |
Times cited |
6 |
Open Access |
|
|
| |
Notes |
We acknowledge the financial support of the EPSRC (Grants EP/I017844/1 and EP/M020517/1), the Leverhulme Trust (RPG-2014-221), and the Diamond Light Source (studentship support for S. J. Cassidy). We thank the ESTEEM2 network for enabling the electron microscopy investigations and the ISIS facility and the Diamond Light Source Ltd. for the award of beam time. We thank Dr. P. Manuel for assistance on WISH, Dr. R. I. Smith for assistance on GEM and POLARIS, and Dr. C. Murray and Dr. A. Baker for assistance on I11. |
Approved |
Most recent IF: 4.857 |
|
| |
Call Number |
EMAT @ emat @ c:irua:136823 |
Serial |
4312 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Tunca, B.; Lapauw, T.; Karakulina, O.M.; Batuk, M.; Cabioc’h, T.; Hadermann, J.; Delville, R.; Lambrinou, K.; Vleugels, J. |
|
| |
Title |
Synthesis of MAX Phases in the Zr-Ti-Al-C System |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
|
| |
Volume |
56 |
Issue |
56 |
Pages |
3489-3498 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
This study reports on the synthesis and characterization of MAX phases in the (Zr,Ti)n+1AlCn system. The MAX phases were synthesized by reactive hot pressing and pressureless sintering in the 1350–1700 °C temperature range. The produced ceramics contained large fractions of 211 and 312 (n = 1, 2) MAX phases, while strong evidence of a 413 (n = 3) stacking was found. Moreover, (Zr,Ti)C, ZrAl2, ZrAl3, and Zr2Al3 were present as secondary phases. In general, the lattice parameters of the hexagonal 211 and 312 phases followed Vegard’s law over the complete Zr-Ti solid solution range, but the 312 phase showed a non-negligible deviation from Vegard’s law around the (Zr0.33,Ti0.67)3Al1.2C1.6 stoichiometry. High-resolution scanning transmission electron microscopy combined with X-ray diffraction demonstrated ordering of the Zr and Ti atoms in the 312 phase, whereby Zr atoms occupied preferentially the central position in the close-packed M6X octahedral layers. The same ordering was also observed in 413 stackings present within the 312 phase. The decomposition of the secondary (Zr,Ti)C phase was attributed to the miscibility gap in the ZrC-TiC system. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000397171100045 |
Publication Date |
2017-03-20 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0020-1669 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.857 |
Times cited |
26 |
Open Access |
OpenAccess |
|
| |
Notes |
Fonds Wetenschappelijk Onderzoek, G.0431.10N.F ; Agentschap voor Innovatie door Wetenschap en Technologie, 131081 ; European Atomic Energy Community, 604862 ; SCK-CEN Academy for Nuclear Science and Technology; Hercules Foundation, Project/Award no: AKUL/1319 Project/Award no: ZW09-09 ; |
Approved |
Most recent IF: 4.857 |
|
| |
Call Number |
EMAT @ emat @ c:irua:141794 |
Serial |
4491 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Batuk, D.; Batuk, M.; Filimonov, D.S.; Zakharov, K.V.; Volkova, O.S.; Vasiliev, A.N.; Tyablikov, O.A.; Hadermann, J.; Abakumov, A.M. |
|
| |
Title |
Crystal Structure, Defects, Magnetic and Dielectric Properties of the Layered Bi3n+1Ti7Fe3n-3,O9n+11 Perovskite-Anatase lntergrowths |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
|
| |
Volume |
56 |
Issue |
56 |
Pages |
931-942 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
The Bi3n+1Ti7Fe3n-3,O9n+11 materials are built of (001)(p) plane parallel perovskite blocks with a thickness of n (Ti,Fe)O-6 octahedra, separated by periodic translational interfaces. The interfaces are based on anatase-like chains of edge -sharing (Ti,Fe)O-6 octahedra. Together with the octahedra of the perovskite blocks, they create S-shaped tunnels stabilized by lone pair Bi3+ cations. In this work, the structure of the n = 4-6 Bi3n+1Ti7Fe3n-3,O9n+11 homologues is analyzed in detail using advanced transmission electron microscopy, powder X-ray diffraction, and Mossbauer spectroscopy. The connectivity of the anatase-like chains to the perovskite blocks results in,a 3ap periodicity along the interfaces, so that they can be located either on top of each other or with shifts of +/- a(p) along [100](p). The ordered arrangement of the interfaces gives rise to orthorhombic Immm and monoclinic A2/m polymorphs with the unit cell parameters a = 3a(p), b = b(p), c = 2(n + 1)c(p) and a = 3a(p), b = b(p), c = 2(n + 1)c(p) – a(p), respectively. While the n = 3 compound is orthorhombic, the monoclinic modification is more favorable in higher homologues. The Bi3n+1Ti7Fe3n-3,O9n+11 structures demonstrate intricate patterns of atomic displacements in the perovskite blocks, which are supported by the stereochemical activity of the Bi3+ cations. These patterns are coupled to the cationic coordination of the oxygen atoms in the (Ti,Fe)O-2 layers at the border of the perovskite blocks. The coupling is strong in the 1/ = 3, 4 homologues, but gradually reduces with the increasing thickness of the perovskite blocks, so that, in the n = 6 compound, the dominant mode of atomic displacements is aligned along the interface planes. The displacements in the adjacent perovskite blocks tend to order antiparallel, resulting in an overall antipolar structure. The Bi3n+1Ti7Fe3n-3,O9n+11 materials demonstrate an unusual diversity of structure defects. The n = 4-6 homologues are robust antiferromagnets below T-N = 135, 220, and 295 K, respectively. They show a high dielectric constant that weakly increases with temperature and is relatively insensitive to the Ti/Fe ratio. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Easton, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000392262400029 |
Publication Date |
2016-12-25 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0020-1669 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.857 |
Times cited |
3 |
Open Access |
Not_Open_Access |
|
| |
Notes |
; The work was supported by the Russian Science Foundation (grant 14-13-00680). ; |
Approved |
Most recent IF: 4.857 |
|
| |
Call Number |
UA @ lucian @ c:irua:141471 |
Serial |
4495 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Jin, L.; Batuk, M.; Kirschner, F.K.K.; Lang, F.; Blundell, S.J.; Hadermann, J.; Hayward, M.A. |
|
| |
Title |
Exsolution of SrO during the Topochemical Conversion of LaSr3CoRuO8to the Oxyhydride LaSr3CoRuO4H4 |
Type |
A1 Journal article |
| |
Year |
2019 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
|
| |
Volume |
58 |
Issue |
21 |
Pages |
14863-14870 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Reaction of the n = 1 Ruddlesden-Popper oxide LaSr3CoRuO8 with CaH2 yields the oxyhydride phase LaSr3CoRuO4H4 via topochemical anion-exchange. Close inspection of X-ray and neutron powder diffraction data in combination with HAADF-STEM images reveals that nanoparticles of SrO are exsolved from the system during the reaction, with the change in cation stoichiometry accommodated by the inclusion of n > 1 (Co/Ru)nOn+1H2n ‘perovskite’ layers into the Ruddlesden-Popper stacking sequence. This novel pseudo-topochemical process offers a new route for the formation of n > 1 Ruddlesden-Popper structured materials. Magnetization data are consistent with a LaSr3Co1+Ru2+O4H4 (Co1+, d8, S = 1; Ru2+, d6, S = 0) oxidation/spin state combination. Neutron diffraction and μ+SR data show no evidence for long-range magnetic order down to 2 K, suggesting the diamagnetic Ru2+ centers impede the Co-Co magnetic exchange interactions. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000494894400062 |
Publication Date |
2019-11-04 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0020-1669 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.857 |
Times cited |
1 |
Open Access |
|
|
| |
Notes |
We thank P. Manuel for assistance collecting the neutron powder diffraction data. We thank The Leverhulme Trust grant award RPG-2014-366 “Topochemical reduction of 4d and 5d transition metal oxides” for supporting this work. 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). Investigation by TEM was supported through the FWO grant G035619N. |
Approved |
Most recent IF: 4.857 |
|
| |
Call Number |
EMAT @ emat @c:irua:164625 |
Serial |
5434 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Abakumov, A.M.; Hadermann, J.; Batuk, M.; d' Hondt, H.; Tyablikov, O.A.; Rozova, M.G.; Pokholok, K.V.; Filimonov, D.S.; Sheptyakov, D.V.; Tsirlin, A.A.; Niermann, D.; Hemberger, J.; Van Tendeloo, G.; Antipov, E.V. |
|
| |
Title |
Slicing the Perovskite structure with crystallographic shear planes : the AnBnO3n-2 homologous series |
Type |
A1 Journal article |
| |
Year |
2010 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
|
| |
Volume |
49 |
Issue |
20 |
Pages |
9508-9516 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
A new AnBnO3n−2 homologous series of anion-deficient perovskites has been evidenced by preparation of the members with n = 5 (Pb2.9Ba2.1Fe4TiO13) and n = 6 (Pb3.8Bi0.2Ba2Fe4.2Ti1.8O16) in a single phase form. The crystal structures of these compounds were determined using a combination of transmission electron microscopy and X-ray and neutron powder diffraction (S.G. Ammm, a = 5.74313(7), b = 3.98402(4), c = 26.8378(4) Å, RI = 0.035, RP = 0.042 for Pb2.9Ba2.1Fe4TiO13 and S.G. Imma, a = 5.7199(1), b = 3.97066(7), c = 32.5245(8) Å, RI = 0.032, RP = 0.037 for Pb3.8Bi0.2Ba2Fe4.2Ti1.8O16). The crystal structures of the AnBnO3n−2 homologues are formed by slicing the perovskite structure with (01)p crystallographic shear (CS) planes. The shear planes remove a layer of oxygen atoms and displace the perovskite blocks with respect to each other by the 1/2[110]p vector. The CS planes introduce edge-sharing connections of the transition metal−oxygen polyhedra at the interface between the perovskite blocks. This results in intrinsically frustrated magnetic couplings between the perovskite blocks due to a competition of the exchange interactions between the edge- and the corner-sharing metal−oxygen polyhedra. Despite the magnetic frustration, neutron powder diffraction and Mssbauer spectroscopy reveal that Pb2.9Ba2.1Fe4TiO13 and Pb3.8Bi0.2Ba2Fe4.2Ti1.8O16 are antiferromagnetically ordered below TN = 407 and 343 K, respectively. The Pb2.9Ba2.1Fe4TiO13 and Pb3.8Bi0.2Ba2Fe4.2Ti1.8O16 compounds are in a paraelectric state in the 5−300 K temperature range. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Easton, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000282783400051 |
Publication Date |
2010-09-24 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0020-1669;1520-510X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.857 |
Times cited |
23 |
Open Access |
|
|
| |
Notes |
Esteem 026019; Fwo |
Approved |
Most recent IF: 4.857; 2010 IF: 4.326 |
|
| |
Call Number |
UA @ lucian @ c:irua:84963 |
Serial |
3041 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Batuk, D.; Batuk, M.; Abakumov, A.M.; Tsirlin, A.A.; McCammon, C.M.; Dubrovinsky, L.; Hadermann, J. |
|
| |
Title |
Effect of lone-electron-pair cations on the orientation of crystallographic shear planes in anion-deficient perovskites |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
|
| |
Volume |
52 |
Issue |
17 |
Pages |
10009-10020 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Factors affecting the structure and orientation of the crystallographic shear (CS) planes in anion-deficient perovskites are investigated using the (Pb1−zSrz)1−xFe1+xO3−y perovskites as a model system. The orientation of the CS planes in the system varies unevenly with z. A comparison of the structures with different CS planes revels that the orientation of the CS planes is governed mainly by the stereochemical activity of the lone-electron-pair cations inside the perovskite blocks. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Easton, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000326129000037 |
Publication Date |
2013-08-22 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0020-1669;1520-510X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.857 |
Times cited |
11 |
Open Access |
|
|
| |
Notes |
Fwo |
Approved |
Most recent IF: 4.857; 2013 IF: 4.794 |
|
| |
Call Number |
UA @ lucian @ c:irua:111394 |
Serial |
822 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Batuk, M.; Batuk, D.; Tsirlin, A.A.; Rozova, M.G.; Antipov, E.V.; Hadermann, J.; Van Tendeloo, G. |
|
| |
Title |
Homologous series of layered perovskites An+1BnO3n-1Cl : crystal and magnetic structure of a new oxychloride Pb4BiFe4O11Cl |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
|
| |
Volume |
52 |
Issue |
4 |
Pages |
2208-2218 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
The nuclear and magnetic structure of a novel oxychloride Pb4BiFe4O11Cl has been studied over the temperature range 1.5700 K using a combination of transmission electron microscopy and synchrotron and neutron powder diffraction [space group P4/mbm, a = 5.5311(1) Å, c = 19.586(1) Å, T = 300 K]. Pb4BiFe4O11Cl is built of truncated (Pb,Bi)3Fe4O11 quadruple perovskite blocks separated by CsCl-type (Pb,Bi)2Cl slabs. The perovskite blocks consist of two layers of FeO6 octahedra located between two layers of FeO5 tetragonal pyramids. The FeO6 octahedra rotate about the c axis, resulting in a √2ap × √2ap × c superstructure. Below TN = 595(17) K, Pb4BiFe4O11Cl adopts a G-type antiferromagnetic structure with the iron magnetic moments confined to the ab plane. The ordered magnetic moments at 1.5 K are 3.93(3) and 3.62(4) μB on the octahedral and square-pyramidal iron sites, respectively. Pb4BiFe4O11Cl can be considered a member of the perovskite-based An+1BnO3n1Cl homologous series (A = Pb/Bi; B = Fe) with n = 4. The formation of a subsequent member of the series with n = 5 is also demonstrated. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Easton, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000315255200067 |
Publication Date |
2013-02-05 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0020-1669;1520-510X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.857 |
Times cited |
6 |
Open Access |
|
|
| |
Notes |
Countatoms |
Approved |
Most recent IF: 4.857; 2013 IF: 4.794 |
|
| |
Call Number |
UA @ lucian @ c:irua:106185 |
Serial |
1486 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Abakumov, A.M.; Batuk, M.; Tsirlin, A.A.; Tyablikov, O.A.; Sheptyakov, D.V.; Filimonov, D.S.; Pokholok, K.V.; Zhidal, V.S.; Rozova, M.G.; Antipov, E.V.; Hadermann, J.; Van Tendeloo, G.; |
|
| |
Title |
Structural and magnetic phase transitions in the AnBnO3n-2 anion-deficient perovskites Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16 |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
|
| |
Volume |
52 |
Issue |
14 |
Pages |
7834-7843 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Novel anion-deficient perovskite-based ferrites Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16 were synthesized by solid-state reaction in air. Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16 belong to the perovskite-based AnBnO3n2 homologous series with n = 5 and 6, respectively, with a unit cell related to the perovskite subcell ap as ap√2 × ap × nap√2. Their structures are derived from the perovskite one by slicing it with 1/2[110]p(1̅01)p crystallographic shear (CS) planes. The CS operation results in (1̅01)p-shaped perovskite blocks with a thickness of (n 2) FeO6 octahedra connected to each other through double chains of edge-sharing FeO5 distorted tetragonal pyramids which can adopt two distinct mirror-related configurations. Ordering of chains with a different configuration provides an extra level of structure complexity. Above T ≈ 750 K for Pb2Ba2BiFe5O13 and T ≈ 400 K for Pb1.5Ba2.5Bi2Fe6O16 the chains have a disordered arrangement. On cooling, a second-order structural phase transition to the ordered state occurs in both compounds. Symmetry changes upon phase transition are analyzed using a combination of superspace crystallography and group theory approach. Correlations between the chain ordering pattern and octahedral tilting in the perovskite blocks are discussed. Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16 undergo a transition into an antiferromagnetically (AFM) ordered state, which is characterized by a G-type AFM ordering of the Fe magnetic moments within the perovskite blocks. The AFM perovskite blocks are stacked along the CS planes producing alternating FM and AFM-aligned FeFe pairs. In spite of the apparent frustration of the magnetic coupling between the perovskite blocks, all n = 4, 5, 6 AnFenO3n2 (A = Pb, Bi, Ba) feature robust antiferromagnetism with similar Néel temperatures of 623632 K. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Easton, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000322087100006 |
Publication Date |
2013-02-13 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0020-1669;1520-510X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.857 |
Times cited |
10 |
Open Access |
|
|
| |
Notes |
Countatoms |
Approved |
Most recent IF: 4.857; 2013 IF: 4.794 |
|
| |
Call Number |
UA @ lucian @ c:irua:109213 |
Serial |
3196 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Batuk, M.; Turner, S.; Abakumov, A.M.; Batuk, D.; Hadermann, J.; Van Tendeloo, G. |
|
| |
Title |
Atomic structure of defects in anion-deficient perovskite-based ferrites with a crystallographic shear structure |
Type |
A1 Journal article |
| |
Year |
2014 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
|
| |
Volume |
53 |
Issue |
4 |
Pages |
2171-2180 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Crystallographic shear (CS) planes provide a new structure-generation mechanism in the anion-deficient perovskites containing lone-pair cations. Pb2Sr2Bi2Fe6O16, a new n = 6 representative of the AnBnO3n2 homologous series of the perovskite-based ferrites with the CS structure, has been synthesized using the solid-state technique. The structure is built of perovskite blocks with a thickness of four FeO6 octahedra spaced by double columns of FeO5 edge-sharing distorted tetragonal pyramids, forming 1/2[110](101)p CS planes (space group Pnma, a = 5.6690(2) Å, b = 3.9108(1) Å, c = 32.643(1) Å). Pb2Sr2Bi2Fe6O16 features a wealth of microstructural phenomena caused by the flexibility of the CS planes due to the variable ratio and length of the constituting fragments with {101}p and {001}p orientation. This leads to the formation of waves, hairpins, Γ-shaped defects, and inclusions of the hitherto unknown layered anion-deficient perovskites Bi2(Sr,Pb)Fe3O8.5 and Bi3(Sr,Pb)Fe4O11.5. Using a combination of diffraction, imaging, and spectroscopic transmission electron microscopy techniques this complex microstructure was fully characterized, including direct determination of positions, chemical composition, and coordination number of individual atomic species. The complex defect structure makes these perovskites particularly similar to the CS structures in ReO3-type oxides. The flexibility of the CS planes appears to be a specific feature of the Sr-based system, related to the geometric match between the SrO perovskite layers and the {100}p segments of the CS planes. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Easton, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000332144100039 |
Publication Date |
2014-01-30 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0020-1669;1520-510X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.857 |
Times cited |
6 |
Open Access |
|
|
| |
Notes |
Countatoms; FWO |
Approved |
Most recent IF: 4.857; 2014 IF: 4.762 |
|
| |
Call Number |
UA @ lucian @ c:irua:113507 |
Serial |
198 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Volykhov, A.A.; Sanchez-Barriga, J.; Batuk, M.; Callaert, C.; Hadermann, J.; Sirotina, A.P.; Neudachina, V.S.; Belova, A.I.; Vladimirova, N.V.; Tamm, M.E.; Khmelevsky, N.O.; Escudero, C.; Perez-Dieste, V.; Knop-Gericke, A.; Yashina, L.V. |
|
| |
Title |
Can surface reactivity of mixed crystals be predicted from their counterparts? A case study of (Bi1-xSbx)2Te3 topological insulators |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
Journal of materials chemistry C : materials for optical and electronic devices |
Abbreviated Journal |
J Mater Chem C |
|
| |
Volume |
6 |
Issue |
33 |
Pages |
8941-8949 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
The behavior of ternary mixed crystals or solid solutions and its correlation with the properties of their binary constituents is of fundamental interest. Due to their unique potential for application in future information technology, mixed crystals of topological insulators with the spin-locked, gapless states on their surfaces attract huge attention of physicists, chemists and material scientists. (Bi1-xSbx)(2)Te-3 solid solutions are among the best candidates for spintronic applications since the bulk carrier concentration can be tuned by varying x to obtain truly bulk-insulating samples, where the topological surface states largely contribute to the transport and the realization of the surface quantum Hall effect. As this ternary compound will be evidently used in the form of thin-film devices its chemical stability is an important practical issue. Based on the atomic resolution HAADF-TEM and EDX data together with the XPS results obtained both ex situ and in situ, we propose an atomistic picture of the mixed crystal reactivity compared to that of its binary constituents. We find that the surface reactivity is determined by the probability of oxygen attack on the Te-Sb bonds, which is directly proportional to the number of Te atoms bonded to at least one Sb atom. The oxidation mechanism includes formation of an amorphous antimony oxide at the very surface due to Sb diffusion from the first two quintuple layers, electron tunneling from the Fermi level of the crystal to oxygen, oxygen ion diffusion to the crystal, and finally, slow Te oxidation to the +4 oxidation state. The oxide layer thickness is limited by the electron transport, and the overall process resembles the Cabrera-Mott mechanism in metals. These observations are critical not only for current understanding of the chemical reactivity of complex crystals, but also to improve the performance of future spintronic devices based on topological materials. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000443279300007 |
Publication Date |
2018-07-20 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2050-7526; 2050-7534 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
5.256 |
Times cited |
3 |
Open Access |
Not_Open_Access |
|
| |
Notes |
; The authors acknowledge financial support within the bilateral program "Russian-German Laboratory at BESSY II''. We thank Helmholtz-Zentrum Berlin for granting access to the beamlines RGBL, UE112-PGM2a and ISISS. Support of ALBA staff during measurements at the CIRCE beamline is gratefully acknowledged. We thank Dr Ivan Bobrikov for support in the XRD measurements and Daria Tsukanova for the participation in crystal preparation and XPS measurements. A. Volykhov thanks RSF (grant 18-73-00248) for financial support. A. I. Belova acknowledges support from the G-RISC Centre of Excellence. The work was supported by Helmholtz Gemeinschaft (Grant No. HRJRG-408) and RFBR (grant 14-03-31518). J. H. and C. C. acknowledge support from the University of Antwerp through the BOF grant 31445. ; |
Approved |
Most recent IF: 5.256 |
|
| |
Call Number |
UA @ lucian @ c:irua:153647 |
Serial |
5080 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Tan, X.; McCabe, E.E.; Orlandi, F.; Manuel, P.; Batuk, M.; Hadermann, J.; Deng, Z.; Jin, C.; Nowik, I.; Herber, R.; Segre, C.U.; Liu, S.; Croft, M.; Kang, C.-J.; Lapidus, S.; Frank, C.E.; Padmanabhan, H.; Gopalan, V.; Wu, M.; Li, M.-R.; Kotliar, G.; Walker, D.; Greenblatt, M. |
|
| |
Title |
MnFe0.5Ru0.5O3 : an above-room-temperature antiferromagnetic semiconductor |
Type |
A1 Journal article |
| |
Year |
2019 |
Publication |
Journal of materials chemistry C : materials for optical and electronic devices |
Abbreviated Journal |
J Mater Chem C |
|
| |
Volume |
7 |
Issue |
3 |
Pages |
509-522 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
A transition-metal-only MnFe0.5Ru0.5O3 polycrystalline oxide was prepared by a reaction of starting materials MnO, MnO2, Fe2O3, RuO2 at 6 GPa and 1873 K for 30 minutes. A combination of X-ray and neutron powder diffraction refinements indicated that MnFe0.5Ru0.5O3 adopts the corundum (alpha-Fe2O3) structure type with space group R (3) over barc, in which all metal ions are disordered. The centrosymmetric nature of the MnFe0.5Ru0.5O3 structure is corroborated by transmission electron microscopy, lack of optical second harmonic generation, X-ray absorption near edge spectroscopy, and Mossbauer spectroscopy. X-ray absorption near edge spectroscopy of MnFe0.5Ru0.5O3 showed the oxidation states of Mn, Fe, and Ru to be 2+/3+, 3+, and similar to 4+, respectively. Resistivity measurements revealed that MnFe0.5Ru0.5O3 is a semiconductor. Magnetic measurements and magnetic structure refinements indicated that MnFe0.5Ru0.5O3 orders antiferromagnetically around 400 K, with magnetic moments slightly canted away from the c axis. Fe-57 Mossbauer confirmed the magnetic ordering and Fe3+ (S = 5/2) magnetic hyperfine splitting. First principles calculations are provided to understand the electronic structure more thoroughly. A comparison of synthesis and properties of MnFe0.5Ru0.5O3 and related corundum Mn2BB'O-6 derivatives is discussed. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000458780300004 |
Publication Date |
2018-11-27 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2050-7526; 2050-7534 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
5.256 |
Times cited |
1 |
Open Access |
Not_Open_Access |
|
| |
Notes |
; M. G. thanks the NSF-DMR-1507252 grant of the United States. X. T. was supported by the “Center for Computational Design of Functional Strongly Correlated Materials and Theoretical Spectroscopy'' under DOE Grant No. DE-FOA-0001276. G. K. and C. J. K. were supported by the Air Force Office of Scientific Research. MRCAT operations are supported by the Department of Energy and the MRCAT member institutions. EEM is grateful to the Leverhulme Trust (RPG-2017-362). M. R. Li and M. X. Wu are supported by the ”One Thousand Youth Talents'' Program of China. Use of the Advanced Photon Source at Argonne National Laboratory was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Part of this research used the ISS, 8-ID and TES, 8-BM beamlines at the National Synchrotron Light Source II (NSLS-II), a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. Without the valuable aid/support of the NSLS-II staff scientists Eli Stavitski, Klaus Attenkofer, and Paul Northrup this phase of the work could not have been performed. The work at IOPCAS was supported by NSF & MOST of China through research projects. H. R. and V. G. acknowledge NSF-MRSEC Center for Nanoscale Science at Penn State through the grant number DMR-1420620. The authors would like to thank Ms Jean Hanley at Lamont-Doherty Earth Observatory in Columbia University for making the high-pressure assemblies. The authors acknowledge the science and technology facility council (STFC) UK for the provision of neutron beam time. The authors would like to thank Daniel Nye for help on the Rigaku SmartLab X-ray diffractometer instrument in the Materials Characterization Laboratory at the ISIS Neutron and Muon Source. ; |
Approved |
Most recent IF: 5.256 |
|
| |
Call Number |
UA @ admin @ c:irua:157564 |
Serial |
5264 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Zhang, F.; Batuk, M.; Hadermann, J.; Manfredi, G.; Mariën, A.; Vanmeensel, K.; Inokoshi, M.; Van Meerbeek, B.; Naert, I.; Vleugels, J. |
|
| |
Title |
Effect of cation dopant radius on the hydrothermal stability of tetragonal zirconia: Grain boundary segregation and oxygen vacancy annihilation |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
Acta materialia |
Abbreviated Journal |
Acta Mater |
|
| |
Volume |
106 |
Issue |
106 |
Pages |
48-58 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
The hydrothermal aging stability of 3Y-TZP-xM2O3 (M = La, Nd, Sc) was investigated as a function of 0.02–5 mol% M2O3 dopant content and correlated to the overall phase content, t-ZrO2 lattice parameters, grain size distribution, grain boundary chemistry and ionic conductivity.
The increased aging stability with increasing Sc2O3 content and the optimum content of 0.4–0.6 mol% Nd2O3 or 0.2–0.4 mol% La2O3, resulting in the highest aging resistance, could be directly related to the constituent phases and the lattice parameters of the remaining tetragonal zirconia.
At low M2O3 dopant contents ≤0.4 mol%, the different aging behavior of tetragonal zirconia was attributed to the defect structure of the zirconia grain boundary which was influenced by the dopant cation radius. It was observed that the grain boundary ionic resistivity and the aging resistance followed the same trend: La3+ > Nd3+ > Al3+ > Sc3+, proving that hydrothermal aging is driven by the diffusion of water-derived mobile species through the oxygen vacancies. Accordingly, we elucidated the underlying mechanism by which a larger trivalent cation segregating at the zirconia grain boundary resulted in a higher aging resistance. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000371650300006 |
Publication Date |
2016-01-08 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1359-6454 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
5.301 |
Times cited |
37 |
Open Access |
|
|
| |
Notes |
The authors acknowledge the Research Fund of KU Leuven under project 0T/10/052 and the Fund for Scientific Research Flanders (FWO-Vlaanderen) under grant G.0431.10N. F. Zhang thanks the Research Fund of KU Leuven for her post-doctoral fellowship (PDM/15/153). |
Approved |
Most recent IF: 5.301 |
|
| |
Call Number |
c:irua:132435 |
Serial |
4076 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Chizhov, As.; Rumyantseva, Mn.; Drozdov, Ka.; Krylov, Iv.; Batuk, M.; Hadermann, J.; Filatova, Dg.; Khmelevsky, No.; Kozlovsky, Vf.; Maltseva, Ln.; Gaskov, Am. |
|
| |
Title |
Photoresistive gas sensor based on nanocrystalline ZnO sensitized with colloidal perovskite CsPbBr3 nanocrystals |
Type |
A1 Journal article |
| |
Year |
2021 |
Publication |
Sensors And Actuators B-Chemical |
Abbreviated Journal |
Sensor Actuat B-Chem |
|
| |
Volume |
329 |
Issue |
|
Pages |
129035 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
The development of sensor materials of which gas sensitivity activates under light illumination is of great importance for the design of portable gas analyzers with low power consumption. In the present work a ZnO/CsPbBr3 nanocomposite based on nanocrystalline ZnO and colloidal cubic-shaped perovskite CsPbBr3 nanocrystals (NCs) capped by oleic acide and oleylamine was synthesized. The individual materials and obtained nanocomposite are characterized by x-ray diffraction, low-temperature nitrogen adsorption, x-ray photoelectron spectroscopy, high angle annular dark field scanning transmission electron microscopy with energy-dispersive Xray spectroscopy mapping and UV-vis absorption spectroscopy. The spectral dependence of the photoconductivity of the ZnO/CsPbBr3 nanocomposite reveals a well-defined peak that strongly correlates with the its optical absorption spectrum. The nanocomposite ZnO/CsPbBr3 shows enhanced photoresponse under visible light illumination (lambda(max) = 470 nm, 8 mW/cm(2)) in air, oxygen and argone, compared with pure nanocrystalline ZnO. Under periodic illumination in the temperature range of 25-100 degrees C, the ZnO/CsPbBr3 nanocomposite shows a sensor response to 0.5-3.0 ppm NO2, unlike pure nanocrystalline ZnO matrix, which demonstrates sensor sensitivity to NO2 under the same conditions above 100 degrees C. The effects of humidity on the sensor signal and photoresponse are also discussed. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000612060700009 |
Publication Date |
2020-10-25 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0925-4005 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
5.401 |
Times cited |
|
Open Access |
OpenAccess |
|
| |
Notes |
The reported study was funded by RFBR according to the research project N◦ 18-33-01004 and in part by a grant from the St. Petersburg State University – Event 3-2018 (id: 46380300). Element mapping for sensors were supported by M.V. Lomonosov Moscow State University Program of Development (X-ray fluorescence spectrometer Tornado M4 plus). |
Approved |
Most recent IF: 5.401 |
|
| |
Call Number |
EMAT @ emat @c:irua:176123 |
Serial |
6707 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Ciocarlan, R.-G.; Seftel, E.M.; Gavrila, R.; Suchea, M.; Batuk, M.; Mertens, M.; Hadermann, J.; Cool, P. |
|
| |
Title |
Spinel nanoparticles on stick-like Freudenbergite nanocomposites as effective smart-removal photocatalysts for the degradation of organic pollutants under visible light |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Journal Of Alloys And Compounds |
Abbreviated Journal |
J Alloy Compd |
|
| |
Volume |
820 |
Issue |
|
Pages |
153403 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA) |
|
| |
Abstract |
A series of mixed nanocomposite materials was synthetized, containing a Ferrite phase type Zn1-xNixFe2O4 and a Freudenbergite phase type Na2Fe2Ti6O16, where x = 0; 0.2; 0.4; 0.6; 0.8; 1. The choice for this combination is based on the good adsorption properties of Freudenbergite for dye molecules, and the small bandgap energy of Ferrite spinel, allowing activation of the catalysts under visible light irradiation. A two steps synthesis protocol was used to obtain the smart-removal nanocomposites. Firstly, the spinel structure was obtained via the co-precipitation route followed by the addition of the Ti-source and formation of the Freudenbergite system. The role of cations on the formation mechanism and an interesting interchange of cations between spinel and Freudenbergite structures was clarified by a TEM study. Part of the Ti4+ penetrated the spinel structure and, at the same time, part of the Fe3+ formed the Freudenbergite system. The photocatalytic activity was studied under visible light, reaching for the best catalysts a 67% and 40% mineralization degree for methylene blue and rhodamine 6G respectively, after 6 h of irradiation. In the same conditions, the well-known commercial P25 (Degussa) managed to mineralize only 12% and 3% of methylene blue and rhodamine 6G, respectively. Due to the remarkable magnetic properties of Ferrites, a convenient recovery and reuse of the catalysts is possible after the photocatalytic tests. Based on the excellent catalytic performance of the nanocomposites under visible light and their ease of separation out of the solution after the catalytic reaction, the newly developed composite catalysts are considered very effective for wastewater treatment. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000507854700130 |
Publication Date |
2019-12-15 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0925-8388 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
6.2 |
Times cited |
|
Open Access |
OpenAccess |
|
| |
Notes |
The authors acknowledge the FWO-Flanders (project nr. G038215N) for financial support. |
Approved |
Most recent IF: 6.2; 2020 IF: 3.133 |
|
| |
Call Number |
EMAT @ emat @c:irua:166447 |
Serial |
6342 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Zhang, F.; Vanmeensel, K.; Batuk, M.; Hadermann, J.; Inokoshi, M.; Van Meerbeek, B.; Naert, I.; Vleugels, J. |
|
| |
Title |
Highly-translucent, strong and aging-resistant 3Y-TZP ceramics for dental restoration by grain boundary segregation |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
Acta biomaterialia |
Abbreviated Journal |
Acta Biomater |
|
| |
Volume |
16 |
Issue |
16 |
Pages |
215-222 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Latest trends in dental restorative ceramics involve the development of full-contour 3Y-TZP ceramics which can avoid chipping of veneering porcelains. Among the challenges are the low translucency and the hydrothermal stability of 3Y-TZP ceramics. In this work, different trivalent oxides (Al2O3, Sc2O3, Nd2O3 and La2O3) were selected to dope 3Y-TZP ceramics. Results show that dopant segregation was a key factor to design hydrothermally stable and high-translucent 3Y-TZP ceramics and the cation dopant radius could be used as a controlling parameter. A large trivalent dopant, oversized as compared to Zr4+, exhibiting strong segregation at the ZrO2 grain boundary was preferred. The introduction of 0.2 mol% La2O3 in conventional 0.10.25 wt.% Al2O3-doped 3Y-TZP resulted in an excellent combination of high translucency and superior hydrothermal stability, while retaining excellent mechanical properties. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
S.l. |
Editor |
|
|
| |
Language |
|
Wos |
000351978600021 |
Publication Date |
2015-02-04 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1742-7061; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
6.319 |
Times cited |
54 |
Open Access |
|
|
| |
Notes |
Fwo G043110n |
Approved |
Most recent IF: 6.319; 2015 IF: 6.025 |
|
| |
Call Number |
c:irua:124421 |
Serial |
1473 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Paulus, A.; Hendrickx, M.; Mayda, S.; Batuk, M.; Reekmans, G.; von Holst, M.; Elen, K.; Abakumov, A.M.; Adriaensens, P.; Lamoen, D.; Partoens, B.; Hadermann, J.; Van Bael, M.K.; Hardy, A. |
|
| |
Title |
Understanding the Activation of Anionic Redox Chemistry in Ti4+-Substituted Li2MnO3as a Cathode Material for Li-Ion Batteries |
Type |
A1 Journal Article |
| |
Year |
2023 |
Publication |
ACS applied energy materials |
Abbreviated Journal |
ACS Appl. Energy Mater. |
|
| |
Volume |
6 |
Issue |
13 |
Pages |
6956-6971 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
|
| |
Abstract |
Layered Li-rich oxides, demonstrating both cationic and anionic redox chemistry being used as positive electrodes for Li-ion batteries,have raised interest due to their high specific discharge capacities exceeding 250 mAh/g. However, irreversible structural transformations triggered by anionic redox chemistry result in pronounced voltagefade (i.e., lowering the specific energy by a gradual decay of discharge potential) upon extended galvanostatic cycling. Activating or suppressing oxygen anionic redox through structural stabilization induced by redox-inactivecation substitution is a well-known strategy. However, less emphasishas been put on the correlation between substitution degree and theactivation/suppression of the anionic redox. In this work, Ti4+-substituted Li2MnO3 was synthesizedvia a facile solution-gel method. Ti4+ is selected as adopant as it contains no partially filled d-orbitals. Our study revealedthat the layered “honeycomb-ordered” C2/m structure is preserved when increasing the Ticontent to x = 0.2 in the Li2Mn1-x Ti (x) O-3 solidsolution, as shown by electron diffraction and aberration-correctedscanning transmission electron microscopy. Galvanostatic cycling hintsat a delayed oxygen release, due to an improved reversibility of theanionic redox, during the first 10 charge-discharge cyclesfor the x = 0.2 composition compared to the parentmaterial (x = 0), followed by pronounced oxygen redoxactivity afterward. The latter originates from a low activation energybarrier toward O-O dimer formation and Mn migration in Li2Mn0.8Ti0.2O3, as deducedfrom first-principles molecular dynamics (MD) simulations for the“charged” state. Upon lowering the Ti substitution to x = 0.05, the structural stability was drastically improvedbased on our MD analysis, stressing the importance of carefully optimizingthe substitution degree to achieve the best electrochemical performance. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
001018266700001 |
Publication Date |
2023-07-10 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2574-0962 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
6.4 |
Times cited |
|
Open Access |
Not_Open_Access: Available from 24.12.2023 |
|
| |
Notes |
Universiteit Hasselt, AUHL/15/2 – GOH3816N ; Russian Science Foundation, 20-43-01012 ; Fonds Wetenschappelijk Onderzoek, AUHL/15/2 – GOH3816N G040116N ; The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the FWO Vlaanderen and the Flemish Government-department EWI. |
Approved |
Most recent IF: 6.4; 2023 IF: NA |
|
| |
Call Number |
EMAT @ emat @c:irua:198160 |
Serial |
8809 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Frolov, A.S.; Callaert, C.; Batuk, M.; Hadermann, J.; Volykhov, A.A.; Sirotina, A.P.; Amati, M.; Gregoratti, L.; Yashina, L.V. |
|
| |
Title |
Nanoscale phase separation in the oxide layer at GeTe (111) surfaces |
Type |
A1 Journal article |
| |
Year |
2022 |
Publication |
Nanoscale |
Abbreviated Journal |
Nanoscale |
|
| |
Volume |
14 |
Issue |
35 |
Pages |
12918-12927 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
As a semiconductor ferroelectric, GeTe has become a focus of renewed attention due to the recent discovery of giant Rashba splitting. It already has a wide range of applications, from thermoelectricity to data storage. Its stability in ambient air, as well as the structure and properties of an oxide layer, define the processing media for device production and operation. Here, we studied a reaction between the GeTe (111) surface and molecular oxygen for crystals having solely inversion domains. We evaluated the reaction kinetics both ex situ and in situ using NAP XPS. The structure of the oxide layer is extensively discussed, where, according to HAADF-STEM and STEM-EDX, nanoscale phase separation of GeO2 and Te is observed, which is unusual for semiconductors. We believe that such behaviour is closely related to the ferroelectric properties and the domain structure of GeTe. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000847743300001 |
Publication Date |
2022-08-25 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2040-3364; 2040-3372 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
|
| |
Impact Factor |
6.7 |
Times cited |
|
Open Access |
Not_Open_Access |
|
| |
Notes |
|
Approved |
Most recent IF: 6.7 |
|
| |
Call Number |
UA @ admin @ c:irua:190665 |
Serial |
7181 |
|
| Permanent link to this record |
