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Author Marikutsa, A.V.; Rumyantseva, M.N.; Frolov, D.D.; Morozov, I.V.; Boltalin, A.I.; Fedorova, A.A.; Petukhov, I.A.; Yashina, L.V.; Konstantinova, E.A.; Sadovskaya, E.M.; Abakumov, A.M.; Zubavichus, Y.V.; Gaskov, A.M.;
Title Role of PdOx and RuOy clusters in oxygen exchange between nanocrystalline tin dioxide and the gas phase Type A1 Journal article
Year 2013 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 117 Issue (up) 45 Pages 23858-23867
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract The effect of palladium- and ruthenium-based clusters on nanocrystalline tin dioxide interaction with oxygen was studied by temperature-programmed oxygen isotopic exchange with mass-spectrometry detection. The modification of aqueous sol-gel prepared SnO2 by palladium and, to a larger extent, by ruthenium, increases surface oxygen concentration on the materials. The revealed effects on oxygen exchange-lowering the threshold temperature, separation of surface oxygen contribution to the process, increase of heteroexchange rate and oxygen diffusion coefficient, decrease of activation energies of exchange and diffusion-were more intensive for Ru-modified SnO2 than in the case of SnO2/Pd. The superior promoting activity of ruthenium on tin dioxide interaction with oxygen was interpreted by favoring the dissociative O-2 adsorption and increasing the oxygen mobility, taking into account the structure and chemical composition of the modifier clusters.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000327110500046 Publication Date 2013-10-04
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 20 Open Access
Notes Approved Most recent IF: 4.536; 2013 IF: 4.835
Call Number UA @ lucian @ c:irua:112706 Serial 2924
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Author Paria Sena, R.; Babaryk, A.A.; Khainakov, S.; Garcia-Granda, S.; Slobodyanik, N.S.; Van Tendeloo, G.; Abakumov, A.M.; Hadermann, J.
Title A pseudo-tetragonal tungsten bronze superstructure: a combined solution of the crystal structure of K6.4(Nb,Ta)36.3O94 with advanced transmission electron microscopy and neutron diffraction Type A1 Journal article
Year 2016 Publication Journal of the Chemical Society : Dalton transactions Abbreviated Journal Dalton T
Volume 45 Issue (up) 45 Pages 973-979
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The crystal structure of the K6.4Nb28.2Ta8.1O94 pseudo-tetragonal tungsten bronze-type oxide was determined using a combination of X-ray powder diffraction, neutron diffraction and transmission electron microscopy techniques, including electron diffraction, high angle annular dark field scanning transmission electron microscopy (HAADF-STEM), annular bright field STEM (ABF-STEM) and energy-dispersive X-ray compositional mapping (STEM-EDX). The compound crystallizes in the space group Pbam with unit cell parameters a = 37.468(9) A, b = 12.493(3) A, c = 3.95333(15) A. The structure consists of corner sharing (Nb,Ta)O6 octahedra forming trigonal, tetragonal and pentagonal tunnels. All tetragonal tunnels are occupied by K(+) ions, while 1/3 of the pentagonal tunnels are preferentially occupied by Nb(5+)/Ta(5+) and 2/3 are occupied by K(+) in a regular pattern. A fractional substitution of K(+) in the pentagonal tunnels by Nb(5+)/Ta(5+) is suggested by the analysis of the HAADF-STEM images. In contrast to similar structures, such as K2Nb8O21, also parts of the trigonal tunnels are fractionally occupied by K(+) cations.
Address Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerp, Belgium. joke.hadermann@uantwerpen.be babaryk@univ.kiev.ua
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Wos 000367614700018 Publication Date 2015-11-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1477-9226 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.029 Times cited 6 Open Access
Notes We thank Dr E. Suard and Dr O. Fabello for assistance in collecting the neutron diffraction data. R.P.S. acknowledges funding from the European Research Council under the 7th Framework Program (FP7), ERC Grant No. 246791-COUNTATOMS. The titan microscope was partly funded by the Hercules fund from the Flemish Government. The authors acknowledge financial support from the European Union under the Seventh Framework Program under a contract for an Integrated Infrastructure Initiative. Reference No. 312483-ESTEEM2. AAB acknowledges the JSPDS ICDD Grant-in-Aid program (12-02).; esteem2jra1; esteem2jra2 Approved Most recent IF: 4.029
Call Number c:irua:130408 c:irua:130408 Serial 3998
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Author Rozova, M.G.; Grigoriev, V.V.; Bobrikov, I.A.; Filimonov, D.S.; Zakharov, K.V.; Volkova, O.S.; Vasiliev, A.N.; Antipov, E.V.; Tsirlin, A.A.; Abakumov, A.M.
Title Synthesis, structure and magnetic ordering of the mullite-type Bi2Fe4-xCrxO9 solid solutions with a frustrated pentagonal Cairo lattice Type A1 Journal article
Year 2016 Publication Journal of the Chemical Society : Dalton transactions Abbreviated Journal Dalton T
Volume 45 Issue (up) 45 Pages 1192-1200
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Highly homogeneous mullite-type solid solutions Bi2Fe4-xCrxO9 (x = 0.5, 1, 1.2) were synthesized using a soft chemistry technique followed by a solid-state reaction in Ar. The crystal structure of Bi2Fe3CrO9 was investigated using X-ray and neutron powder diffraction, transmission electron microscopy and Fe-57 Mossbauer spectroscopy (S.G. Pbam, a = 7.95579(9) angstrom , b = 8.39145(9) angstrom, c = 5.98242(7) angstrom, R-F(X-ray) = 0.022, R-F(neutron) = 0.057). The ab planes in the structure are tessellated with distorted pentagonal loops built up by three tetrahedrally coordinated Fe sites and two octahedrally coordinated Fe/Cr sites, linked together in the ab plane by corner-sharing forming a pentagonal Cairo lattice. Magnetic susceptibility measurements and powder neutron diffraction show that the compounds order antiferromagnetically (AFM) with the Neel temperatures decreasing upon increasing the Cr content from T-N similar to 250 K for x = 0 to T-N similar to 155 K for x = 1.2. The magnetic structure of Bi2Fe3CrO9 at T = 30 K is characterized by a propagation vector k = (1/2,1/2,1/2). The tetrahedrally coordinated Fe cations form singlet pairs within dimers of corner-sharing tetrahedra, but spins on the neighboring dimers are nearly orthogonal. The octahedrally coordinated (Fe, Cr) cations form antiferromagnetic up-up-down-down chains along c, while the spin arrangement in the ab plane is nearly orthogonal between nearest neighbors and collinear between second neighbors. The resulting magnetic structure is remarkably different from the one in pure Bi2Fe4O9 and features several types of spin correlations even on crystallographically equivalent exchange that may be caused by the simultaneous presence of Fe and Cr on the octahedral site.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000367614700041 Publication Date 2015-11-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0300-9246; 1477-9226; 1472-7773 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.029 Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:131095 Serial 4257
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Author Abakumov, A.M.; Rossell, M.D.; Seryakov, S.A.; Rozova, M.G.; Markina, M.M.; Van Tendeloo, G.; Antipov, E.V.
Title Synthesis and crystal structure of novel CaRMnSnO6(R = La, Pr, Nd, Sm-Dy) double perovskites Type A1 Journal article
Year 2005 Publication Journal of materials chemistry Abbreviated Journal J Mater Chem
Volume 15 Issue (up) 46 Pages 4899-4905
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000233439300005 Publication Date 2005-10-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0959-9428;1364-5501; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 8 Open Access
Notes Iap V-1 Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:56069 Serial 3424
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Author Zaikina, J.V.; Batuk, M.; Abakumov, A.M.; Navrotsky, A.; Kauziarich, S.M.
Title Facile synthesis of Ba1-xKxFe2As2 superconductors via hydride route Type A1 Journal article
Year 2014 Publication Journal of the American Chemical Society Abbreviated Journal J Am Chem Soc
Volume 136 Issue (up) 48 Pages 16932-16939
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We have developed a fast, easy, and scalable synthesis method for Ba1xKxFe2As2 (0 ≤ x ≤ 1) superconductors using hydrides BaH2 and KH as a source of barium and potassium metals. Synthesis from hydrides provides better mixing and easier handling of the starting materials, consequently leading to faster reactions and/or lower synthesis temperatures. The reducing atmosphere provided by the evolved hydrogen facilitates preparation of oxygen-free powders. By a combination of methods we have shown that Ba1xKxFe2As2 obtained via hydride route has the same characteristics as when it is prepared by traditional solid-state synthesis. Refinement from synchrotron powder X-ray diffraction data confirms a linear dependence of unit cell parameters upon K content as well as the tetragonal to orthorhombic transition at low temperatures for compositions with x < 0.2. Magnetic measurements revealed dome-like dependence of superconducting transition temperature Tc upon K content with a maximum of 38 K for x close to 0.4. Electron diffraction and high-resolution high-angle annular dark-field scanning transmission electron microscopy indicates an absence of Ba/K ordering, while local inhomogeneity in the Ba/K distribution takes place at a scale of several angstroms along [110] crystallographic direction.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000345883900040 Publication Date 2014-11-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0002-7863;1520-5126; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 13.858 Times cited 13 Open Access
Notes Approved Most recent IF: 13.858; 2014 IF: 12.113
Call Number UA @ lucian @ c:irua:121331 Serial 1169
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Author Ovsyannikov, S.V.; Karkin, A.E.; Morozova, N.V.; Shchennikov, V.V.; Bykova, E.; Abakumov, A.M.; Tsirlin, A.A.; Glazyrin, K.V.; Dubrovinsky, L.
Title A hard oxide semiconductor with a direct and narrow bandgap and switchable pn electrical conduction Type A1 Journal article
Year 2014 Publication Advanced materials Abbreviated Journal Adv Mater
Volume 26 Issue (up) 48 Pages 8185-8191
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract An oxide semiconductor (perovskite-type Mn2O3) is reported which has a narrow and direct bandgap of 0.45 eV and a high Vickers hardness of 15 GPa. All the known materials with similar electronic band structures (e.g., InSb, PbTe, PbSe, PbS, and InAs) play crucial roles in the semiconductor industry. The perovskite-type Mn2O3 described is much stronger than the above semiconductors and may find useful applications in different semiconductor devices, e.g., in IR detectors.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000346480800016 Publication Date 2014-10-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0935-9648; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 19.791 Times cited 27 Open Access
Notes Approved Most recent IF: 19.791; 2014 IF: 17.493
Call Number UA @ lucian @ c:irua:122230 Serial 1408
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Author Serov, T.V.; Dombrovski, E.N.; Ardashnikova, E.I.; Dolgikh, V.A.; el Omari, M.; el Omari, M.; Abaouz, A.; Senegas, J.; Chaban, N.G.; Abakumov, A.M.; Van Tendeloo, G.
Title Fluorite-like phases in the BaF2-BiF3-Bi2O3 system-synthesis, conductivity and defect clustering Type A1 Journal article
Year 2005 Publication Materials research bulletin Abbreviated Journal Mater Res Bull
Volume 40 Issue (up) 5 Pages 821-830
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000229376500012 Publication Date 2005-03-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0025-5408; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.446 Times cited 4 Open Access
Notes Iap V-1 Approved Most recent IF: 2.446; 2005 IF: 1.380
Call Number UA @ lucian @ c:irua:54838 Serial 1240
Permanent link to this record
 
 
Author Tsirlin, A.A.; Abakumov, A.M.; Van Tendeloo, G.; Rosner, H.
Title Interplay of atomic displacement in the quantum magnet (CuCI)LaNb2O7 Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue (up) 5 Pages 054107,1-054107,12
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We report on the crystal structure of the quantum magnet CuClLaNb2O7 that was controversially described with respect to its structural organization and magnetic behavior. Using high-resolution synchrotron powder x-ray diffraction, electron diffraction, transmission electron microscopy, and band-structure calculations, we solve the room-temperature structure of this compound -CuClLaNb2O7 and find two high-temperature polymorphs. The -CuClLaNb2O7 phase, stable above 640 K, is tetragonal with asub=3.889 Å, csub =11.738 Å, and the space group P4/mmm. In the -CuClLaNb2O7 structure, the Cu and Cl atoms are randomly displaced from the special positions along the 100 directions. The phase asub2asubcsub, space group Pbmm and the phase 2asub2asubcsub, space group Pbam are stable between 640 K and 500 K and below 500 K, respectively. The structural changes at 500 and 640 K are identified as order-disorder phase transitions. The displacement of the Cl atoms is frozen upon the → transformation while a cooperative tilting of the NbO6 octahedra in the phase further eliminates the disorder of the Cu atoms. The low-temperature -CuClLaNb2O7 structure thus combines the two types of the atomic displacements that interfere due to the bonding between the Cu atoms and the apical oxygens of the NbO6 octahedra. The precise structural information resolves the controversy between the previous computation-based models and provides the long-sought input for understanding CuClLaNb2O7 and related compounds with unusual magnetic properties.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000280849400001 Publication Date 2010-08-12
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 13 Open Access
Notes Approved Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:83991 Serial 1706
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Author Vassiliev, S.Y.; Laurinavichute, V.K.; Abakumov, A.M.; Govorov, V.A.; Bendovskii, E.B.; Turner, S.; Filatov, A.Y.; Tarasovskii, V.P.; Borzenko, A.G.; Alekseeva, A.M.; Antipov, E.V.
Title Microstructural aspects of the degradation behavior of SnO2-based anodes for aluminum electrolysis Type A1 Journal article
Year 2010 Publication Journal of the electrochemical society Abbreviated Journal J Electrochem Soc
Volume 157 Issue (up) 5 Pages C178-C186
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The performance of SnO2 ceramic anodes doped with copper and antimony oxides was examined in cryolite alumina melts under anodic polarization at different cryolite ratios, temperatures, times, and current densities. The corroded part consists of a narrow strong corrosion zone at the anode surface with damage of the intergrain contacts and a large increase in porosity, a wider moderate corrosion zone with a smaller porosity increase, and a Cu depletion zone, where the ceramic retains its initial microstructure and a slight porosity increase occurs due to the removal of the Cu-rich inclusions. Mechanical destruction of the anode was never observed in the 10100 h tests. A microstructural model of the ceramic was suggested, consisting of grains with an Sb-doped SnO2 grain core surrounded by an ~200 to 500 nm grain shell where SnO2 was simultaneously doped with Sb and Mn+ (M=Cu2+,Fe3+,Al3+). The grains were separated by a few nanometers thick Cu-enriched grain boundaries. Different secondary charge carrier (holes) concentrations and electric conductivities in the grain core and grain shell result in a higher current density at the intergrain regions that leads to their profound degradation, especially in the low temperature acidic melt.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000276555300037 Publication Date 2010-04-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0013-4651; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.259 Times cited 3 Open Access
Notes Approved Most recent IF: 3.259; 2010 IF: 2.427
Call Number UA @ lucian @ c:irua:82260 Serial 2040
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Author Ovsyannikov, S.V.; Abakumov, A.M.; Tsirlin, A.A.; Schnelle, W.; Egoavil, R.; Verbeeck, J.; Van Tendeloo, G.; Glazyrin, K.V.; Hanfland, M.; Dubrovinsky, L.
Title Perovskite-like Mn2O3 : a path to new manganites Type A1 Journal article
Year 2013 Publication Angewandte Chemie Abbreviated Journal Angew Chem Int Edit
Volume 52 Issue (up) 5 Pages 1494-1498
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Korund-artiges ε-Mn2O3 und Perowskit-artiges ζ-Mn2O3, zwei neue Phasen von Mn2O3, wurden unter hohen Drücken bei hohen Temperaturen synthetisiert. Die Manganatome können vollständig die A- und B-Positionen der Perowskitstruktur besetzen. ζ-Mn2O3 (siehe Bild, A-Positionsordnung) enthält Mn in den drei Oxidationsstufen +II, +III und +IV.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000313913300027 Publication Date 2012-12-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1433-7851; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 11.994 Times cited 84 Open Access
Notes This work was supported by the DFG (project OV-110/1-1), Alexander von Humboldt foundation, European Union Council (FP7)-Grant no. 246102 IFOX, European Research Council (FP7)-ERC Starting Grant no. 278510 VORTEX and ERC Grant no. 246791-COUNTATOMS, and Hercules fund from the Flemish Government. ECASJO_; Approved Most recent IF: 11.994; 2013 IF: 11.336
Call Number UA @ lucian @ c:irua:108765UA @ admin @ c:irua:108765 Serial 2573
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Author Vasiliev, R.B.; Babynina, A.V.; Maslova, O.A.; Rumyantseva, M.N.; Ryabova, L.I.; Dobrovolsky, A.A.; Drozdov, K.A.; Khokhlov, D.R.; Abakumov, A.M.; Gaskov, A.M.
Title Photoconductivity of nanocrystalline SnO2 sensitized with colloidal CdSe quantum dots Type A1 Journal article
Year 2013 Publication Journal of materials chemistry C : materials for optical and electronic devices Abbreviated Journal J Mater Chem C
Volume 1 Issue (up) 5 Pages 1005-1010
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A highly reproducible photoresponse is observed in nanocrystalline SnO2 thick films sensitized with CdSe quantum dots. The effect of the SnO2 matrix microstructure on the photoconductivity kinetics and photoresponse amplitude is demonstrated. The photoresponse of the sensitized SnO2 thick films reaches more than two orders of magnitude under illumination with the wavelength of the excitonic transition of the quantum dots. Long-term photoconductivity kinetics and photoresponse dependence on illumination intensity reveal power-law behavior inherent to the disordered nature of SnO2. The photoconductivity of the samples rises with the coarsening of the granular structure of the SnO2 matrix. At the saturation region, the photoresponse amplitude remains stable under 10(4) pulses of illumination switching, demonstrating a remarkably high stability.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000314803600016 Publication Date 2012-11-14
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 13 Open Access
Notes Approved Most recent IF: 5.256; 2013 IF: NA
Call Number UA @ lucian @ c:irua:107705 Serial 2610
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Author Panin, R.V.; Khasanova, N.R.; Abakumov, A.M.; Antipov, E.V.; Van Tendeloo, G.; Schnelle, W.
Title Synthesis and crystal structure of the palladium oxides NaPd3O4, Na2PdO3 and K3Pd2O4 Type A1 Journal article
Year 2007 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume 180 Issue (up) 5 Pages 1566-1574
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000246892800007 Publication Date 2007-03-13
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 24 Open Access
Notes Approved Most recent IF: 2.299; 2007 IF: 2.149
Call Number UA @ lucian @ c:irua:64740 Serial 3429
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Author Prituzhalov, V.A.; Abakumov, A.M.; Ardashnikova, E.I.; Dolgikh, V.A.; Van Tendeloo, G.
Title :Ba2.1Bi0.9(O, F)6.8-\delta: a new ordered anion-excess fluorite Type A1 Journal article
Year 2007 Publication Materials research bulletin Abbreviated Journal Mater Res Bull
Volume 42 Issue (up) 5 Pages 861-869
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000245842600010 Publication Date 2006-10-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0025-5408; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.446 Times cited 4 Open Access
Notes Approved Most recent IF: 2.446; 2007 IF: 1.484
Call Number UA @ lucian @ c:irua:64724 Serial 3515
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Author Pachoud, E.; Bréard, Y.; Martin, C.; Maignan, A.; Abakumov, A.M.; Suard, E.; Smith, R.I.; Suchomel, M.R.
Title Bi0.75Sr0.25FeO3-\delta : revealing order/disorder phenomena by combining diffraction techniques Type A1 Journal article
Year 2012 Publication Solid state communications Abbreviated Journal Solid State Commun
Volume 152 Issue (up) 5 Pages 331-336
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The local and long range structure of polycrystalline samples of Bi0.75Sr0.25FeO3-delta has been probed by neutron and synchrotron X-ray diffraction coupled with transmission electron microscopy. It is found that the long range structure on average can be described by the cubic space group Pm-3m (a(p) congruent to 3.951 angstrom). However, the refinements revealed large atomic displacements for the (Bi, Sr) cations and the oxygen atoms from their ideal positions. The electron microscopy study indicates the existence of local phenomena like local ordering of oxygen vacancies, which are segregated at the randomly spaced parallel (FeO2-delta) planes, or the existence of region of different symmetry, probably R3c. At room temperature, the compound exhibits G-type antiferromagnetism (T-N congruent to 650 K) with a magnetic moment of congruent to 3.7 mu(B). (C) 2012 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000301329200001 Publication Date 2011-12-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0038-1098; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.554 Times cited 6 Open Access
Notes Approved Most recent IF: 1.554; 2012 IF: 1.534
Call Number UA @ lucian @ c:irua:97820 Serial 3516
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Author Abakumov, A.M.; Hadermann, J.; Van Tendeloo, G.; Kovba, M.L.; Skolis, Y.Y.; Mudretsova, S.N.; Antipov, E.V.; Volkova, O.S.; Vasiliev, A.N.; Tristan, N.; Klingeler, R.; Büchner, B.
Title [SrF0.8(OH)0.2]2.526[Mn6O12]: columnar rock-salt fragments inside the todorokite-type tunnel structure Type A1 Journal article
Year 2007 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 19 Issue (up) 5 Pages 1181-1189
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000244467800035 Publication Date 2007-02-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 9 Open Access
Notes Iap V-1 Approved Most recent IF: 9.466; 2007 IF: 4.883
Call Number UA @ lucian @ c:irua:62525 Serial 3561
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Author Mikhailova, D.; Kuratieva, N.N.; Utsumi, Y.; Tsirlin, A.A.; Abakumov, A.M.; Schmidt, M.; Oswald, S.; Fuess, H.; Ehrenberg, H.
Title Composition-dependent charge transfer and phase separation in the V1-xRexO2 solid solution Type A1 Journal article
Year 2017 Publication Journal of the Chemical Society : Dalton transactions Abbreviated Journal
Volume 46 Issue (up) 5 Pages 1606-1617
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The substitution of vanadium in vanadium dioxide VO2 influences the critical temperatures of structural and metal-to-insulator transitions in different ways depending on the valence of the dopant. Rhenium adopts valence states between + 4 and + 7 in an octahedral oxygen surrounding and is particularly interesting in this context. Structural investigation of V1-xRexO2 solid solutions (0.01 <= x <= 0.30) between 80 and 1200 K using synchrotron X-ray powder diffraction revealed only two polymorphs that resemble VO2: the low-temperature monoclinic MoO2-type form (space group P2(1)/c), and the tetragonal rutile-like form (space group P4(2)/mnm). However, for compositions with 0.03 < x <= 0.15 a phase separation in the solid solution was observed below 1000 K upon cooling down from 1200 K, giving rise to two isostructural phases with slightly different lattice parameters. This is reflected in the appearance of two metal-toinsulator transition temperatures detected by magnetization and specific heat measurements. Comprehensive X-ray photoelectron spectroscopy studies showed that an increased amount of Re leads to a change in the Re valence state from solely Re6+ at a low doping level (<= 3 at% Re) via mixed-valence states Re4+/Re6+ for at least 0.03 < x <= 0.10, up to nearly pure Re4+ in V0.70Re0.30O2. Thus, compositions V1-xRexO2 with only one valence state of Re in the material (Re6+ or Re4+) can be obtained as a single phase, while intermediate compositions are subjected to a phase separation, presumably due to different valence states of Re.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000395442700030 Publication Date 2016-12-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0300-9246; 1477-9226; 1472-7773 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.029 Times cited 1 Open Access Not_Open_Access
Notes ; The authors are indebted to Dr G. Auffermann (Max Planck Institute for Chemical Physics of Solids, Dresden, Germany) for performing the ICP-OES analyses. This research has received a partial funding from the BMBF, project grant number 03SF0477B (DESIREE). AT acknowledges financial support from Federal Ministry for Education and Research under Sofja Kovalevksaya Award of Alexander von Humboldt Foundation. AMA is grateful to the Russian Science Foundation (grant 14-13-00680) for financial support. ; Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:142580 Serial 4642
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Author Pearce, P.E.; Perez, A.J.; Rousse, G.; Saubanère, M.; Batuk, D.; Foix, D.; McCalla, E.; Abakumov, A.M.; Van Tendeloo, G.; Doublet, M.-L.; Tarascon, J.-M.
Title Evidence for anionic redox activity in a tridimensional-ordered Li-rich positive electrode β-Li2IrO3 Type A1 Journal article
Year 2017 Publication Nature materials Abbreviated Journal Nat Mater
Volume 16 Issue (up) 5 Pages 580-586
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Lithium-ion battery cathode materials have relied on cationic redox reactions until the recent discovery of anionic redox activity in Li-rich layered compounds which enables capacities as high as 300 mAh g(-1). In the quest for new high-capacity electrodes with anionic redox, a still unanswered question was remaining regarding the importance of the structural dimensionality. The present manuscript provides an answer. We herein report on a beta-Li2IrO3 phase which, in spite of having the Ir arranged in a tridimensional (3D) framework instead of the typical two-dimensional (2D) layers seen in other Li-rich oxides, can reversibly exchange 2.5 e(-) per Ir, the highest value ever reported for any insertion reaction involving d-metals. We show that such a large activity results from joint reversible cationic (Mn+) and anionic (O-2)(n-) redox processes, the latter being visualized via complementary transmission electron microscopy and neutron diffraction experiments, and confirmed by density functional theory calculations. Moreover, beta-Li2IrO3 presents a good cycling behaviour while showing neither cationic migration nor shearing of atomic layers as seen in 2D-layered Li-rich materials. Remarkably, the anionic redox process occurs jointly with the oxidation of Ir4+ at potentials as low as 3.4 V versus Li+/Li-0, as equivalently observed in the layered alpha-Li2IrO3 polymorph. Theoretical calculations elucidate the electrochemical similarities and differences of the 3D versus 2D polymorphs in terms of structural, electronic and mechanical descriptors. Our findings free the structural dimensionality constraint and broaden the possibilities in designing high-energy-density electrodes for the next generation of Li-ion batteries.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000400004200018 Publication Date 2017-02-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1476-1122 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 39.737 Times cited Open Access Not_Open_Access
Notes The authors thank Q. Jacquet for fruitful discussions and V. Pomjakushin for his valuable help in neutron diffraction experiments. This work is based on experiments performed at the Swiss Spallation Neutron Source SINQ, Paul Scherrer Institute, Villigen, Switzerland. Use of the 11-BM mail service of the APS at Argonne National Laboratory was supported by the US Department of Energy under contract No. DE-AC02-06CH11357 and is greatly acknowledged. J.-M.T. acknowledges funding from the European Research Council (ERC) (FP/2014)/ERC Grant-Project 670116-ARPEMA. E.M. acknowledges financial support from the Fonds de Recherche du Quebec-Nature et Technologies. Approved Most recent IF: 39.737
Call Number EMAT @ emat @c:irua:147502 Serial 4773
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Author Alekseeva, A.M.; Abakumov, A.M.; Leither-Jasper, A.; Schnelle, W.; Prots, Y.; Van Tendeloo, G.; Antipov, E.V.; Grin, Y.
Title Spatial separation of covalent, ionic, and metallic interactions in Mg11Rh18B8 and Mg3Rh5B3 Type A1 Journal article
Year 2013 Publication Chemistry: a European journal Abbreviated Journal Chem-Eur J
Volume 19 Issue (up) 52 Pages 17860-17870
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The crystal structures of Mg11Rh18B8 and Mg3Rh5B3 have been investigated by using single-crystal X-ray diffraction. Mg11Rh18B8: space group P4/mbm; a=17.9949(7), c=2.9271(1)angstrom; Z=2. Mg3Rh5B3: space group Pmma; a=8.450(2), b=2.8644(6), c=11.602(2)angstrom; Z=2. Both crystal structures are characterized by trigonal prismatic coordination of the boron atoms by rhodium atoms. The [BRh6] trigonal prisms form arrangements with different connectivity patterns. Analysis of the chemical bonding by means of the electron-localizability/electron-density approach reveals covalent BRh interactions in these arrangements and the formation of BRh polyanions. The magnesium atoms that are located inside the polyanions interact ionically with their environment, whereas, in the structure parts, which are mainly formed by Mg and Rh atoms, multicenter (metallic) interactions are observed. Diamagnetic behavior and metallic electron transport of the Mg11Rh18B8 and Mg3Rh5B3 phases are in agreement with the bonding picture and the band structure.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000328531000028 Publication Date 2013-12-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0947-6539; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.317 Times cited 5 Open Access
Notes Approved Most recent IF: 5.317; 2013 IF: 5.696
Call Number UA @ lucian @ c:irua:113697 Serial 3064
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Author Batuk, D.; Batuk, M.; Tsirlin, A.A.; Hadermann, J.; Abakumov, A.M.
Title Trapping of Oxygen Vacancies at Crystallographic Shear Planes in Acceptor-Doped Pb-Based Ferroelectrics Type A1 Journal article
Year 2015 Publication Angewandte Chemie: international edition in English Abbreviated Journal Angew Chem Int Edit
Volume 54 Issue (up) 54 Pages 14787-14790
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The defect chemistry of the ferroelectric material PbTiO3 after doping with Fe(III) acceptor ions is reported. Using advanced transmission electron microscopy and powder X-ray and neutron diffraction, we demonstrate that even at concentrations as low as circa 1.7% (material composition approximately ABO2.95), the oxygen vacancies are trapped into extended planar defects, specifically crystallographic shear planes. We investigate the evolution of these defects upon doping and unravel their detailed atomic structure using the formalism of superspace crystallography, thus unveiling their role in nonstoichiometry in the Pb-based perovskites.
Address Chemistry Department, Moscow State University, 119991, Moscow (Russia). artem.abakumov@uantwerpen.be
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Wos 000367723400031 Publication Date 2015-10-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1433-7851 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 11.994 Times cited 3 Open Access
Notes A.M.A. is grateful to the Russian Science Foundation (grant 14-13-00680). AT was funded by the Mobilitas grant MTT77 of the ESF and by the Federal Ministry for Education and Research through the Sofja Kovalevskaya Award of Alexander von Humboldt Foundation. Approved Most recent IF: 11.994; 2015 IF: 11.261
Call Number c:irua:131104 Serial 4080
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Author Batuk, D.; Tsirlin, A.A.; Filimonov, D.S.; Zakharov, K.V.; Volkova, O.S.; Vasiliev, A.; Hadermann, J.; Abakumov, A.M.
Title Bi(3n+1)Ti7Fe(3n-3)O(9n+11) Homologous Series: Slicing Perovskite Structure with Planar Interfaces Containing Anatase-like Chains Type A1 Journal article
Year 2016 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
Volume 55 Issue (up) 55 Pages 1245-1257
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The n = 3-6 members of a new perovskite-based homologous series Bi(3n+1)Ti7Fe(3n-3)O(9n+11) are reported. The crystal structure of the n = 3 Bi10Ti7Fe6O38 member is refined using a combination of X-ray and neutron powder diffraction data (a = 11.8511(2) A, b = 3.85076(4) A, c = 33.0722(6) A, S.G. Immm), unveiling the partially ordered distribution of Ti(4+) and Fe(3+) cations and indicating the presence of static random displacements of the Bi and O atoms. All Bi(3n+1)Ti7Fe(3n-3)O(9n+11) structures are composed of perovskite blocks separated by translational interfaces parallel to the (001)p perovskite planes. The thickness of the perovskite blocks increases with n, while the atomic arrangement at the interfaces remains the same. The interfaces comprise chains of double edge-sharing (Fe,Ti)O6 octahedra connected to the octahedra of the perovskite blocks by sharing edges and corners. This configuration shifts the adjacent perovskite blocks relative to each other over a vector (1/2)[110]p and creates S-shaped tunnels along the [010] direction. The tunnels accommodate double columns of the Bi(3+) cations, which stabilize the interfaces owing to the stereochemical activity of their lone electron pairs. The Bi(3n+1)Ti7Fe(3n-3)O(9n+11) structures can be formally considered either as intergrowths of perovskite modules and polysynthetically twinned modules of the Bi2Ti4O11 structure or as intergrowths of the 2D perovskite and 1D anatase fragments. Transmission electron microscopy (TEM) on Bi10Ti7Fe6O38 reveals that static atomic displacements of Bi and O inside the perovskite blocks are not completely random; they are cooperative, yet only short-range ordered. According to TEM, the interfaces can be laterally shifted with respect to each other over +/-1/3a, introducing an additional degree of disorder. Bi10Ti7Fe6O38 is paramagnetic in the 1.5-1000 K temperature range due to dilution of the magnetic Fe(3+) cations with nonmagnetic Ti(4+). The n = 3, 4 compounds demonstrate a high dielectric constant of 70-165 at room temperature.
Address Center for Electrochemical Energy Storage, Skolkovo Institute of Science and Technology , Nobelya str. 3, 143026 Moscow, Russia
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Wos 000369356800031 Publication Date 2016-01-09
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
Notes We are grateful to the Laboratory for Neutron Scattering and Imaging of Paul Scherrer Institut (LNS PSI, Villigen, Switzerland) for granting beam time at the HRPT diffrac- tometer and to Dr. Denis Sheptyakov for the technical support during the experiment. We are also grateful to Valery Verchenko for his help with magnetization measurements. The work has been supported by the Russian Science Foundation (grant 14-13-00680). A.A.T. was partly supported by the Federal Ministry for Education and Science through a Sofja Kovalevskaya Award of Alexander von Humboldt Foundation. Approved Most recent IF: 4.857
Call Number c:irua:132247 Serial 4073
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Author Retuerto, M.; Skiadopoulou, S.; Li, M.R.; Abakumov, A.M.; Croft, M.; Ignatov, A.; Sarkar, T.; Abbett, B.M.; Pokorný, J.; Savinov, M.; Nuzhnyy, D.; Prokleška, J.; Abeykoon, M.; Stephens, P.W.; Hodges, J.P.; Vaněk, P.; Fennie, C.J.; Rabe, K.M.; Kamba, S.; Greenblatt, M.;
Title Pb2MnTeO6 double perovskite : an antipolar anti-ferromagnet Type A1 Journal article
Year 2016 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
Volume 55 Issue (up) 55 Pages 4320-4329
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Pb2MnTeO6, a new double perovskite, was synthesized. Its crystal structure was determined by synchrotron X-ray and powder neutron diffraction. Pb2MnTeO6 is monoclinic (I2/m) at room temperature with a regular arrangement of all the cations in their polyhedra. However, when the temperature is lowered to similar to 120 K it undergoes a phase transition from I2/m to C2/c structure. This transition is accompanied by a displacement of the Pb atoms from the center of their polyhedra due to the 6s2 lone-pair electrons, together with a surprising off-centering of Mn2+ (d5) magnetic cations. This strong first-order phase transition is also evidenced by specific heat, dielectric, Raman, and infrared spectroscopy measurements. The magnetic characterizations indicate an anti-ferromagnetic (AFM) order below TN approximate to 20 K; analysis of powder neutron diffraction data confirms the magnetic structure with propagation vector k = (0 1 0) and collinear AFM spins. The observed jump in dielectric permittivity near similar to 150 K implies possible anti-ferroelectric behavior; however, the absence of switching suggests that Pb2MnTeO6 can only be antipolar. First-principle calculations confirmed that the crystal and magnetic structures determined are locally stable and that anti-ferroelectric switching is unlikely to be observed in Pb2MnTeO6.
Address
Corporate Author Thesis
Publisher Place of Publication Easton, Pa Editor
Language Wos 000375519700027 Publication Date 2016-04-08
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 9 Open Access
Notes Approved Most recent IF: 4.857
Call Number UA @ lucian @ c:irua:134219 Serial 4258
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Author Mikhailova, D.; Karakulina, O.M.; Batuk, D.; Hadermann, J.; Abakumov, A.M.; Herklotz, M.; Tsirlin, A.A.; Oswald, S.; Giebeler, L.; Schmidt, M.; Eckert, J.; Knapp, M.; Ehrenberg, H.
Title Layered-to-Tunnel Structure Transformation and Oxygen Redox Chemistry in LiRhO2upon Li Extraction and Insertion Type A1 Journal article
Year 2016 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
Volume 55 Issue (up) 55 Pages 7079-7089
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Layered Li(M,Li)O2 (where M is a transition metal) ordered rock-salt-type structures are used in advanced metal-ion batteries as one of the best hosts for the reversible intercalation of Li ions. Besides the conventional redox reaction involving oxidation/reduction of the M cation upon Li extraction/insertion, creating oxygen-located holes because of the partial oxygen oxidation increases capacity while maintaining the oxidized oxygen species in the lattice through high covalency of the M–O bonding. Typical degradation mechanism of the Li(M,Li)O2 electrodes involves partially irreversible M cation migration toward the Li positions, resulting in gradual capacity/voltage fade. Here, using LiRhO2 as a model system (isostructural and isoelectronic to LiCoO2), for the first time, we demonstrate an intimate coupling between the oxygen redox and M cation migration. A formation of the oxidized oxygen species upon electrochemical Li extraction coincides with transformation of the layered Li1–xRhO2 structure into the γ-MnO2-type rutile–ramsdellite intergrowth LiyRh3O6 structure with rutile-like [1 × 1] channels along with bigger ramsdellite-like [2 × 1] tunnels through massive and concerted Rh migration toward the empty positions in the Li layers. The oxidized oxygen dimers with the O–O distances as short as 2.26 Å are stabilized in this structure via the local Rh–O configuration reminiscent to that in the μ-peroxo-μ-hydroxo Rh complexes. The LiyRh3O6 structure is remarkably stable upon electrochemical cycling illustrating that proper structural implementation of the oxidized oxygen species can open a pathway toward deliberate employment of the anion redox chemistry in high-capacity/high-voltage positive electrodes for metal-ion batteries. Upon chemical or electrochemical oxidation, layered LiRhO2 shows a unique structural transformation that involves both cation migration and oxidation of oxygen resulting in a stable tunnel-like rutile−ramsdellite intergrowth LiyRh3O6 structure. This structure demonstrates excellent performance with the steady and reversible capacity of ∼200 mAh/g. The stability of LiyRh3O6 is rooted in the accommodation of partially oxidized oxygen species through the formation of short O−O distances that are compatible with the connectivity of RhO6 octahedra.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000380181400035 Publication Date 2016-07-18
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 12 Open Access
Notes Bundesministerium fur Bildung und Forschung, 03SF0477B ; Fonds Wetenschappelijk Onderzoek, G040116N ; Approved Most recent IF: 4.857
Call Number EMAT @ emat @ c:irua:140848 Serial 4424
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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 (up) 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
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Author Forsh, E.A.; Abakumov, A.M.; Zaytsev, V.B.; Konstantinova, E.A.; Forsh, P.A.; Rumyantseva, M.N.; Gaskov, A.M.; Kashkarov, P.K.
Title Optical and photoelectrical properties of nanocrystalline indium oxide with small grains Type A1 Journal article
Year 2015 Publication Thin solid films : an international journal on the science and technology of thin and thick films Abbreviated Journal Thin Solid Films
Volume 595 Issue (up) 595 Pages 25-31
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Optical properties, spectral dependence of photoconductivity and photoconductivity decay in nanocrystalline indium oxide In2O3 are studied. A number of nanostructured In2O3 samples with various nanocrystals size are prepared by sol-gel method and characterized using various techniques. The mean nanocrystals size varies from 7 to 8 nm to 39-41 nm depending on the preparation conditions. Structural characterization of the In2O3 samples is performed by means of transmission electron microscopy and X-ray powder diffraction. The combined analysis of ultraviolet-visible absorption spectroscopy and diffuse reflectance spectroscopy shows that nanostructuring leads to the change in optical band gap: optical band gap of the In2O3 samples (with an average nanocrystal size from 7 to 41 nm) is equal to 2.8 eV. We find out the correlation between spectral dependence of photoconductivity and optical properties of nanocrystalline In2O3: sharp increase in photoconductivity was observed to begin at 2.8 eV that is equal to the optical bandgap in the In2O3 samples, and reached its maximum at 3.2-3.3 eV. The combined analysis of the slow photoconductivity decay in air, vacuum and argon, that was accurately fitted by a stretched-exponential function, and electron paramagnetic resonance (EPR) measurements shows that the kinetics of photoconductivity decay is strongly depended on the presence of oxygen molecules in the ambient of In2O3 nanocrystals. There is the quantitative correlation between EPR and photoconductivity data. Based on the obtained data we propose the model clearing up the phenomenon of permanent photoconductivity decay in nanocrystalline In2O3. (C) 2015 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Lausanne Editor
Language Wos 000365812400005 Publication Date 2015-10-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0040-6090 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.879 Times cited 18 Open Access
Notes Approved Most recent IF: 1.879; 2015 IF: 1.759
Call Number UA @ lucian @ c:irua:130254 Serial 4219
Permanent link to this record
 
 
Author Abakumov, A.M.; Hadermann, J.; Van Tendeloo, G.; Antipov, E.V.
Title Chemistry and structure of anion-deficient perovskites with translational interfaces Type A1 Journal article
Year 2008 Publication Journal of the American Ceramic Society Abbreviated Journal J Am Ceram Soc
Volume 91 Issue (up) 6 Pages 1807-1813
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Columbus, Ohio Editor
Language Wos 000256410700010 Publication Date 2008-04-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0002-7820;1551-2916; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.841 Times cited 39 Open Access
Notes Approved Most recent IF: 2.841; 2008 IF: 2.101
Call Number UA @ lucian @ c:irua:70088 Serial 355
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Author Bourgeois, J.; Hervieu, M.; Poienar, M.; Abakumov, A.M.; Elkaïm, E.; Sougrati, M.T.; Porcher, F.; Damay, F.; Rouquette, J.; Van Tendeloo, G.; Maignan, A.; Haines, J.; Martin, C.;
Title Evidence of oxygen-dependent modulation in LuFe2O4 Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 85 Issue (up) 6 Pages 064102-064120,10
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A polycrystalline sample of LuFe2O4 has been investigated by means of powder synchrotron x-ray and neutron diffraction and transmission electron microscopy (TEM), along with Mössbauer spectroscopy and transport and magnetic properties. A monoclinic distortion is unambiguously evidenced, and the crystal structure is refined in the monoclinic C2/m space group [aM = 5.9563(1) Å, bM = 3.4372(1) Å, cM = 8.6431(1) Å, β = 103.24(1)°]. Along with the previously reported modulations distinctive of the charge-ordering (CO) of the iron species, a new type of incommensurate order is observed, characterized by a vector q⃗1 = α1a⃗M* + γ1c⃗M* (with α1 ≅ 0.55, γ1 ≅ 0.13). In situ heating TEM observations from 300 to 773 K confirm that the satellites associated with q⃗1 vanish completely, only at a temperature significantly higher than the CO temperature. This incommensurate modulation has a displacive character and corresponds primarily to a transverse displacive modulation wave of the Lu cations position, as revealed by the high resolution, high angle annular dark field scanning TEM images and in agreement with synchrotron data refinements. Analyses of vacuum-annealed samples converge toward the hypothesis of a new ordering mechanism, associated with a tiny oxygen deviation from the O4 stoichiometry.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000299896900003 Publication Date 2012-02-06
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 24 Open Access
Notes Hercules Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:95042 Serial 1095
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Author Lieberman, C.M.; Filatov, A.S.; Wei, Z.; Rogachev, A.Y.; Abakumov, A.M.; Dikarev, E.V.
Title Mixed-valent, heteroleptic homometallic diketonates as templates for the design of volatile heterometallic precursors Type A1 Journal article
Year 2015 Publication Chemical science Abbreviated Journal Chem Sci
Volume 6 Issue (up) 6 Pages 2835-2842
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A novel series of mixed-valent, heteroleptic transition metal diketonates that can be utilized as prospective single-source precursors for the low-temperature preparation of oxide materials are reported. The first mixed-valent iron beta-diketonates with different Fe-III/Fe-II ratios have been synthesized by applying the mixed-ligand approach. Based on nearly quantitative reaction yields and analysis of iron-oxygen bonds, these compounds were formulated as [Fe-III(acac)(3)][Fe-II(hfac)(2)] (1) and [Fe-II(hfac)(2)][Fe-III(acac)(3)][Fe-II(hfac)(2)] (2). In the above heteroleptic complexes, the Lewis acidic, coordinatively unsaturated Fe-II centers chelated by two hfac (hexafluoroacetylacetonate) ligands with electron-withdrawing substituents maintain bridging interactions with oxygen atoms of electron-donating acac (acetylacetonate) groups that chelate the neighboring Fe-III atoms. Switching the ligands on Fe-III and Fe-II atoms in starting reagents resulted in the instant ligand exchange between iron centers and in yet another polynuclear homometallic diketonate [Fe-II(hfac)(2)][Fe-III(acac)(2)(hfac)][Fe-II(hfac)(2)] (3) that adheres to the same bonding pattern as in complexes 1 and 2. The proposed synthetic methodology has been extended to design heterometallic diketonates with different M : M' ratios. Homometallic parent molecules have been used as templates to obtain heterometallic mixed-valent [Fe-III(acac)(3)][Mn-II(hfac)(2)] (4) and [Ni-II(hfac)(2)] – [Fe-III(acac)(3)][Ni-II(hfac)(2)] (5) complexes. The combination of two different diketonate ligands with electron-donating and electron-withdrawing substituents was found to be crucial for maintaining the above mixed-valent heterometallic assemblies. Theoretical investigation of two possible “isomers”, [Fe-III(acac)(3)][Mn-II(hfac)(2)] (4) and [Mn-III(acac)(3)][Fe-II(hfac)(2)] (40) provided an additional support for the metal site assignment giving a preference of 9.78 kcal mol(-1) for the molecule 4. Heterometallic complexes obtained in the course of this study have been found to act as effective single-source precursors for the synthesis of mixed-transition metal oxide materials MxM2-xO3 and MxMi-xO. The title highly volatile precursors can be used for the low-temperature preparation of both amorphous and crystalline heterometallic oxides in the form of thin films or nanosized particles that are known to operate as efficient catalysts in oxygen evolution reaction.
Address
Corporate Author Thesis
Publisher Royal Society of Chemistry Place of Publication Cambridge Editor
Language Wos 000353223100021 Publication Date 2015-02-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2041-6520;2041-6539; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.668 Times cited 13 Open Access
Notes Approved Most recent IF: 8.668; 2015 IF: 9.211
Call Number c:irua:126031 Serial 2092
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Author Caignaert, V.; Abakumov, A.M.; Pelloquin, D.; Pralong, V.; Maignan, A.; Van Tendeloo, G.; Raveau, B.
Title A new mixed-valence ferrite with a cubic structure, YBaFe4O7: spin-glass-like behavior Type A1 Journal article
Year 2009 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 21 Issue (up) 6 Pages 1116-1122
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A new mixed-valence ferrite, YBaFe4O7, has been synthesized. Its unique cubic structure, with a = 8.9595(2) Å, is closely related to that of the hexagonal 114 oxides YBaCo4O7 and CaBaFe4O7. It consists of corner-sharing FeO4 tetrahedra, forming triangular and kagome layers parallel to (111)C. In fact, the YBaFe4O7 and CaBaFe4O7 structures can be described as two different ccc and chch close packings of [BaO3]∞ and [O4]∞ layers, respectively, whose tetrahedral cavities are occupied by Fe2+/Fe3+ cations. The local structure of YBaFe4O7 is characterized by a large amount of stacking faults originating from the presence of hexagonal layers in the ccc cubic close-packed YBaFe4O7 structure. In this way, they belong to the large family of spinels and hexagonal ferrites studied for their magnetic properties. Differently from all the ferrites and especially from CaBaFe4O7, which are ferrimagnetic, YBaFe4O7 is an insulating spin glass with Tg = 50 K.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000264310900019 Publication Date 2009-02-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 39 Open Access
Notes Esteem 026019 Approved Most recent IF: 9.466; 2009 IF: 5.368
Call Number UA @ lucian @ c:irua:76432 Serial 2325
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Author Gou, H.; Tsirlin, A.A.; Bykova, E.; Abakumov, A.M.; Van Tendeloo, G.; Richter, A.; Ovsyannikov, S.V.; Kurnosov, A.V.; Trots, D.M.; Konôpková, Z.; Liermann, H.P.; Dubrovinsky, L.; Dubrovinskaia, N.;
Title Peierls distortion, magnetism, and high hardness of manganese tetraboride Type A1 Journal article
Year 2014 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 89 Issue (up) 6 Pages 064108-64109
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We report crystal structure, electronic structure, and magnetism of manganese tetraboride, MnB4, synthesized under high-pressure, high-temperature conditions. In contrast to superconducting FeB4 and metallic CrB4, which are both orthorhombic, MnB4 features a monoclinic crystal structure. Its lower symmetry originates from a Peierls distortion of the Mn chains. This distortion nearly opens the gap at the Fermi level, but despite the strong dimerization and the proximity of MnB4 to the insulating state, we find indications for a sizable paramagnetic effective moment of about 1.7 mu(B)/f.u., ferromagnetic spin correlations, and, even more surprisingly, a prominent electronic contribution to the specific heat. However, no magnetic order has been observed in standard thermodynamic measurements down to 2 K. Altogether, this renders MnB4 a structurally simple but microscopically enigmatic material; we argue that its properties may be influenced by electronic correlations.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000332405000002 Publication Date 2014-02-24
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 39 Open Access
Notes Approved Most recent IF: 3.836; 2014 IF: 3.736
Call Number UA @ lucian @ c:irua:115819 Serial 2571
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Author Hadermann, J.; Van Tendeloo, G.; Abakumov, A.M.; Pavlyuk, B.P.; Rozova, M.G.; Antipov, E.V.
Title Structural transformation in fluorinated LaACuGaO5 (A=Ca, Sr) brownmillerites Type A1 Journal article
Year 2000 Publication International journal of inorganic materials Abbreviated Journal Int J Inorg Mater
Volume 2 Issue (up) 6 Pages 493-502
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000165985400005 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1466-6049; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 13 Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:36043 Serial 3265
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