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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.; url  doi
openurl 
  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 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 (down) 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  
Permanent link to this record
 

 
Author Tsirlin, A.A.; Nath, R.; Abakumov, A.M.; Furukawa, Y.; Johnston, D.C.; Hemmida, M.; Krug von Nidda, H.-A.; Loidl, A.; Geibel, C.; Rosner, H. url  doi
openurl 
  Title Phase separation and frustrated square lattice magnetism of Na1.5VOPO4F0.5 Type A1 Journal article
  Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B  
  Volume 84 Issue 1 Pages 014429-014429,16  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Crystal structure, electronic structure, and magnetic behavior of the spin-1/2 quantum magnet Na1.5VOPO4F0.5 are reported. The disorder of Na atoms leads to a sequence of structural phase transitions revealed by synchrotron x-ray powder diffraction and electron diffraction. The high-temperature second-order α↔β transition at 500 K is of the order-disorder type, whereas the low-temperature β↔γ+γ′ transition around 250 K is of the first order and leads to a phase separation toward the polymorphs with long-range (γ) and short-range (γ′) order of Na. Despite the complex structural changes, the magnetic behavior of Na1.5VOPO4F0.5 probed by magnetic susceptibility, heat capacity, and electron spin resonance measurements is well described by the regular frustrated square lattice model of the high-temperature α-polymorph. The averaged nearest-neighbor and next-nearest-neighbor couplings are J̅ 1≃−3.7 K and J̅ 2≃6.6 K, respectively. Nuclear magnetic resonance further reveals the long-range ordering at TN=2.6 K in low magnetic fields. Although the experimental data are consistent with the simplified square-lattice description, band structure calculations suggest that the ordering of Na atoms introduces a large number of inequivalent exchange couplings that split the square lattice into plaquettes. Additionally, the direct connection between the vanadium polyhedra induces an unusually strong interlayer coupling having effect on the transition entropy and the transition anomaly in the specific heat. Peculiar features of the low-temperature crystal structure and the relation to isostructural materials suggest Na1.5VOPO4F0.5 as a parent compound for the experimental study of tetramerized square lattices as well as frustrated square lattices with different values of spin.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000293247400008 Publication Date 2011-07-28  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 47 Open Access  
  Notes Approved Most recent IF: 3.836; 2011 IF: 3.691  
  Call Number UA @ lucian @ c:irua:91770 Serial 2588  
Permanent link to this record
 

 
Author Tsirlin, A.A.; Abakumov, A.M.; Ritter, C.; Henry, P.F.; Janson, O.; Rosner, H. url  doi
openurl 
  Title Short-range order of Br and three-dimensional magnetism in (CuBr)LaNb2O7 Type A1 Journal article
  Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B  
  Volume 85 Issue 21 Pages 214427  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract We present a comprehensive study of the crystal structure, magnetic structure, and microscopic magnetic model of (CuBr)LaNb2O7, the Br analog of the spin-gap quantum magnet (CuCl) LaNb2O7. Despite similar crystal structures and spin lattices, the magnetic behavior and even peculiarities of the atomic arrangement in the Cl and Br compounds are very different. The high- resolution x-ray and neutron data reveal a split position of Br atoms in (CuBr) LaNb2O7. This splitting originates from two possible configurations developed by [CuBr] zigzag ribbons. While the Br atoms are locally ordered in the ab plane, their arrangement along the c direction remains partially disordered. The predominant and energetically more favorable configuration features an additional doubling of the c lattice parameter that was not observed in (CuCl) LaNb2O7. (CuBr) LaNb2O7 undergoes long-range antiferromagnetic ordering at T-N = 32 K, which is nearly 70% of the leading exchange coupling J4 similar or equal to 48 K. The Br compound does not show any experimental signatures of low-dimensional magnetism because the underlying spin lattice is three-dimensional. The coupling along the c direction is comparable to the couplings in the ab plane, even though the shortest Cu-Cu distance along c (11.69 angstrom) is three times larger than nearest-neighbor distances in the ab plane (3.55 angstrom). The stripe antiferromagnetic long-range order featuring columns of parallel spins in the ab plane and antiparallel spins along c is verified experimentally and confirmed by the microscopic analysis.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000305557600002 Publication Date 2012-06-22  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 5 Open Access  
  Notes Approved Most recent IF: 3.836; 2012 IF: 3.767  
  Call Number UA @ lucian @ c:irua:100289 Serial 2998  
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Author Abakumov, A.M.; Tsirlin, A.A.; Perez-Mato, J.M.; Petřiček, V.; Rosner, H.; Yang, T.; Greenblatt, M. url  doi
openurl 
  Title Spiral ground state against ferroelectricity in the frustrated magnet BiMnFe2O6 Type A1 Journal article
  Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B  
  Volume 83 Issue 21 Pages 214402-214402,10  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract The spiral magnetic structure and underlying spin lattice of BiMnFe2O6 are investigated by low-temperature neutron powder diffraction and density functional theory band structure calculations. In spite of the random distribution of the Mn3+ and Fe3+ cations, this centrosymmetric compound undergoes a transition into an incommensurate antiferromagnetically ordered state below TN≃220 K. The magnetic structure is characterized by the propagation vector k=[0,β,0] with β≃0.14 and the P221211′(0β0)0s0s magnetic superspace symmetry. It comprises antiferromagnetic helixes propagating along the b axis. The magnetic moments lie in the ac plane and rotate about π(1+β)≃204.8-deg angle between the adjacent magnetic atoms along b. The spiral magnetic structure arises from the peculiar frustrated arrangement of exchange couplings in the ab plane. The antiferromagnetic coupling along the c axis cancels the possible electric polarization and prevents ferroelectricity in BiMnFe2O6.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000291197400001 Publication Date 2011-06-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 12 Open Access  
  Notes Approved Most recent IF: 3.836; 2011 IF: 3.691  
  Call Number UA @ lucian @ c:irua:90080 Serial 3107  
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Author Tsirlin, A.A.; Abakumov, A.M.; Ritter, C.; Rosner, H. url  doi
openurl 
  Title (CuCl)LaTa2O\text{7} and quantum phase transition in the (CuX)LaM2O7 family (X=Cl, Br; M=Nb, Ta) Type A1 Journal article
  Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B  
  Volume 86 Issue 6 Pages 064440-12  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract We apply neutron diffraction, high-resolution synchrotron x-ray diffraction, magnetization measurements, electronic structure calculations, and quantum Monte-Carlo simulations to unravel the structure and magnetism of (CuCl)LaTa2O7. Despite the pseudo-tetragonal crystallographic unit cell, this compound features an orthorhombic superstructure, similar to the Nb-containing (CuX)LaNb2O7 with X = Cl and Br. The spin lattice entails dimers formed by the antiferromagnetic fourth-neighbor coupling J(4), as well as a large number of nonequivalent interdimer couplings quantified by an effective exchange parameter J(eff). In (CuCl)LaTa2O7, the interdimer couplings are sufficiently strong to induce the long-range magnetic order with the Neel temperature T-N similar or equal to 7 K and the ordered magnetic moment of 0.53 mu(B), as measured with neutron diffraction. This magnetic behavior can be accounted for by J(eff)/J(4) similar or equal to 1.6 and J(4) similar or equal to 16 K. We further propose a general magnetic phase diagram for the (CuCl)LaNb2O7-type compounds, and explain the transition from the gapped spin-singlet (dimer) ground state in (CuCl)LaNb2O7 to the long-range antiferromagnetic order in (CuCl)LaTa2O7 and (CuBr)LaNb2O7 by an increase in the magnitude of the interdimer couplings J(eff)/J(4), with the (CuCl)LaM2O7 (M = Nb, Ta) compounds lying on different sides of the quantum critical point that separates the singlet and long-range-ordered magnetic ground states.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000308127600006 Publication Date 2012-08-29  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 6 Open Access  
  Notes Approved Most recent IF: 3.836; 2012 IF: 3.767  
  Call Number UA @ lucian @ c:irua:101886 Serial 3526  
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Author Meert, K.W.; Morozov, V.A.; Abakumov, A.M.; Hadermann, J.; Poelman, D.; Smet, P.F. url  doi
openurl 
  Title Energy transfer in Eu3+ doped scheelites : use as thermographic phosphor Type A1 Journal article
  Year 2014 Publication Optics express Abbreviated Journal Opt Express  
  Volume 22 Issue 9 Pages A961-A972  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract In this paper the luminescence of the scheelite-based CaGd2(1-x)Eu2x(WO4)4 solid solutions is investigated as a function of the Eu content and temperature. All phosphors show intense red luminescence due to the 5D0 7F2 transition in Eu3+, along with other transitions from the 5D1 and 5D0 excited states. For high Eu3+ concentrations the intensity ratio of the emission originating from the 5D1 and 5D0 levels has a non-conventional temperature dependence, which could be explained by a phonon-assisted cross-relaxation process. It is demonstrated that this intensity ratio can be used as a measure of temperature with high spatial resolution, allowing the use of these scheelites as thermographic phosphor. The main disadvantage of many thermographic phosphors, a decreasing signal for increasing temperature, is absent.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000335905300037 Publication Date 2014-04-22  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 1094-4087; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.307 Times cited 47 Open Access  
  Notes Approved Most recent IF: 3.307; 2014 IF: 3.488  
  Call Number UA @ lucian @ c:irua:117067 Serial 1044  
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Author Panin, R.V.; Khasanova, N.R.; Abakumov, A.M.; Schnelle, W.; Hadermann, J.; Antipov, E.V. doi  openurl
  Title Crystal structure and properties of the Na1-xRu2O4 phase Type A1 Journal article
  Year 2006 Publication Russian chemical bulletin Abbreviated Journal Russ Chem B+  
  Volume 55 Issue 10 Pages 1717-1722  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000245091400003 Publication Date 2007-03-07  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 1066-5285;1573-9171; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 0.529 Times cited 5 Open Access  
  Notes Approved Most recent IF: 0.529; 2006 IF: 0.505  
  Call Number UA @ lucian @ c:irua:63810 Serial 566  
Permanent link to this record
 

 
Author Kalyuzhnaya, A.S.; Abakumov, A.M.; Rozova, M.G.; d' Hondt, H.; Hadermann, J.; Antipov, E.V. doi  openurl
  Title Synthesis and crystal structure of the new complex oxide Ca7Mn2.14Ga5.86O17.93 Type A1 Journal article
  Year 2010 Publication Russian chemical bulletin Abbreviated Journal Russ Chem B+  
  Volume 59 Issue 4 Pages 706-711  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract The complex oxide Ca7Mn2.14Ga5.86O17.93 was synthesized by the solid-state reaction in a sealed evacuated quartz tube at 1000 °C. Its crystal structure was determined by electron diffraction and X-ray powder diffraction. The structure can be represented as a tetrahedral framework, viz., the polyanion [(Mn0.285Ga0.715)15O29.86]19- stabilized by the incorporated cation [Ca14GaO6]19+. The polycation consists of the GaO6 octahedra surrounded by the Ca atoms, which are arranged to form a cube capped at all places. The tetrahedral framework is partially disordered due to the presence of tetrahedra with two possible orientations in the positions (0, 0, 0) and (x, x, x) with x ≈ 0.15 and 0.17. The relationship between the Ca7Mn2.14Ga5.86O17.93 structures and related ordered phases with the symmetry F23, as well as the influence of the oxygen content on the ordering in the tetrahedral framework, are discussed.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000283302000006 Publication Date 2010-10-20  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 1066-5285;1573-9171; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 0.529 Times cited 1 Open Access  
  Notes Approved Most recent IF: 0.529; 2010 IF: 0.629  
  Call Number UA @ lucian @ c:irua:85675 Serial 3427  
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Author Mazo, G.N.; Savvin, S.N.; Abakumov, A.M.; Hadermann, J.; Dobrovol'skii, Y.A.; Leonova, L.S. doi  openurl
  Title Lanthanum-strontium cuprate as a promising cathodic matreila for solid oxide fuel cells Type A1 Journal article
  Year 2007 Publication Russian journal of electrochemistry Abbreviated Journal Russ J Electrochem+  
  Volume 43 Issue 4 Pages 436-442  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000246338500010 Publication Date 2007-05-09  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 1023-1935;1608-3342; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 0.828 Times cited 8 Open Access  
  Notes Approved Most recent IF: 0.828; 2007 IF: 0.263  
  Call Number UA @ lucian @ c:irua:62062 Serial 1777  
Permanent link to this record
 

 
Author Van Tendeloo, G.; Hadermann, J.; Abakumov, A.M.; Antipov, E.V. pdf  doi
openurl 
  Title Advanced electron microscopy and its possibilities to solve complex structures: application to transition metal oxides Type A1 Journal article
  Year 2009 Publication Journal of materials chemistry Abbreviated Journal J Mater Chem  
  Volume 19 Issue 18 Pages 2660-2670  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Design and optimization of materials properties can only be performed through a thorough knowledge of the structure of the compound. In this feature article we illustrate the possibilities of advanced electron microscopy in materials science and solid state chemistry. The different techniques are briefly discussed and several examples are given where the structures of complex oxides, often with a modulated structure, have been solved using electron microscopy.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Cambridge Editor  
  Language Wos 000265740600002 Publication Date 2009-02-04  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0959-9428;1364-5501; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited 9 Open Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ lucian @ c:irua:77065 Serial 68  
Permanent link to this record
 

 
Author Abakumov, A.M.; Rossell, M.D.; Seryakov, S.A.; Rozova, M.G.; Markina, M.M.; Van Tendeloo, G.; Antipov, E.V. pdf  doi
openurl 
  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 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 (down) 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  
Permanent link to this record
 

 
Author Hadermann, J.; Abakumov, A.M.; d' Hondt, H.; Kalyuzhnaya, A.S.; Rozova, M.G.; Markina, M.M.; Mikheev, M.G.; Tristan, N.; Klingeler, R.; Büchner, B.; Antipov, E.V. pdf  doi
openurl 
  Title Synthesis and crystal structure of the Sr2Al1.07Mn0.93O5 brownmillerite Type A1 Journal article
  Year 2007 Publication Journal of materials chemistry Abbreviated Journal J Mater Chem  
  Volume 17 Issue 7 Pages 692-698  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Cambridge Editor  
  Language Wos 000244085100016 Publication Date 2006-12-15  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0959-9428;1364-5501; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited 31 Open Access  
  Notes Iap V-1 Approved Most recent IF: NA  
  Call Number UA @ lucian @ c:irua:62061 Serial 3430  
Permanent link to this record
 

 
Author Kirsanova, M.A.; Reshetova, L.N.; Olenev, A.V.; Abakumov, A.M.; Shevelkov, A.V. doi  openurl
  Title Semiclathrates of the GePTe system : synthesis and crystal structures Type A1 Journal article
  Year 2011 Publication Chemistry: a European journal Abbreviated Journal Chem-Eur J  
  Volume 17 Issue 20 Pages 5719-5726  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Novel compounds [Ge46−xPx]Tey (13.9≤x≤15.6, 5.92≤y≤7.75) with clathrate-like structures have been prepared and structurally characterized. They crystallize in the space group Fmequation image with the unit cell parameter changing from 20.544(2) to 20.698(2) Å (Z=8) on going from x=13.9 to x=15.6. Their crystal structure is composed of a covalently bonded Ge[BOND]P framework that hosts tellurium atoms in the guest positions and can be viewed as a peculiar variant of the type I clathrate superstructure. In contrast to the conventional type I clathrates, [Ge46−xPx]Tey contain tricoordinated (3b) atoms and no vacancies in the framework positions. As a consequence of the transformation of the framework, the majority of the guest tellurium atoms form a single covalent bond with the host framework and thus the title compounds are the first representative of semiclathrates with covalent bonding. A comparison is made with silicon clathrates and the evolution of the crystal structure upon changing the tellurium content is discussed.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Weinheim Editor  
  Language Wos 000290216000028 Publication Date 2011-04-05  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0947-6539; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 5.317 Times cited 17 Open Access  
  Notes Approved Most recent IF: 5.317; 2011 IF: 5.925  
  Call Number UA @ lucian @ c:irua:89773 Serial 2981  
Permanent link to this record
 

 
Author Alekseeva, A.M.; Abakumov, A.M.; Leither-Jasper, A.; Schnelle, W.; Prots, Y.; Van Tendeloo, G.; Antipov, E.V.; Grin, Y. pdf  doi
openurl 
  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 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 (down) 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  
Permanent link to this record
 

 
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. pdf  url
doi  openurl
  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 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 (down) 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  
Permanent link to this record
 

 
Author Zhukova, A.A.; Rumyantseva, M.N.; Zaytsev, V.B.; Zaytseva, A.V.; Abakumov, A.M.; Gaskov, A.M. doi  openurl
  Title Pd nanoparticles on SnO2(Sb) whiskers : aggregation and reactivity in CO detection Type A1 Journal article
  Year 2013 Publication Journal of alloys and compounds Abbreviated Journal J Alloy Compd  
  Volume 565 Issue Pages 6-10  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Single crystal antimony-doped SnO2 whiskers have been synthesized by in situ doping process in horizontal flow reactor. The produced whiskers were modified with 0.1, 0.2, 0.5, 1 or 2 wt.% Pd. The processes of Pd particles growth and aggregation are described on the base of AFM and STEM data. Depending on the content of introduced Pd precursor, the various mechanisms (Volmer-Weber or Stranski-Krastanov) of Pd nanoparticles growth realize. The dependence of sensor signal to CO on Pd concentration has non-monotonous character determined by the size of Pd nanoparticles and their aggregation degree. The best sensor signal toward CO was observed for whiskers decorated with 0.1 wt.% Pd. This concentration corresponds to the presence of individual 3-5 nm Pd nanoparticles on the surface of the whiskers. (C) 2013 Elsevier B.V. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000317815300002 Publication Date 2013-03-13  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0925-8388; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.133 Times cited Open Access  
  Notes Approved Most recent IF: 3.133; 2013 IF: 2.726  
  Call Number UA @ lucian @ c:irua:108424 Serial 2566  
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Author Bramnik, K.G.; Abakumov, A.M.; Shpanchenko, R.V.; Antipov, E.V.; Van Tendeloo, G. doi  openurl
  Title Synthesis and structure of Ln4Re6-xO19 (Ln=Ce, Pr, Nd) complex oxides Type A1 Journal article
  Year 1998 Publication Journal of alloys and compounds Abbreviated Journal J Alloy Compd  
  Volume 278 Issue Pages 98-102  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000075799200020 Publication Date 2002-07-25  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0925-8388; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.133 Times cited 8 Open Access  
  Notes Approved Most recent IF: 3.133; 1998 IF: 0.880  
  Call Number UA @ lucian @ c:irua:25677 Serial 3444  
Permanent link to this record
 

 
Author Zakharova, E.Y.; Kazakov, S.M.; Isaeva, A.A.; Abakumov, A.M.; Van Tendeloo, G.; Kuznetsov, A.N. doi  openurl
  Title Pd5InSe and Pd8In2Se : new metal-rich homological selenides with 2D palladium-indium fragments : synthesis, structure and bonding Type A1 Journal article
  Year 2014 Publication Journal of alloys and compounds Abbreviated Journal J Alloy Compd  
  Volume 589 Issue Pages 48-55  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Two new metal-rich palladium-indium selenides, Pd5InSe and Pd8In2Se, were synthesized using a high-temperature ampoule technique. Their crystal structures were determined from Rietveld analysis of powder diffraction data, supported by energy-dispersive X-ray spectroscopy and selected area electron diffraction. Both compounds crystallize in tetragonal system with P4/mmm space group (Pd5InSe: a = 4.0290(3) angstrom, c = 6.9858(5) angstrom, Z = 1; Pd8In2Se: a = 4.0045(4) angstrom, c = 10.952(1) angstrom, Z = 1). The first compound belongs to the Pd5TlAs structure type, while the second one – to a new structure type. Main structural units in both selenides are indium-centered [Pd12In] cuboctahedra of the tetragonally distorted Cu3Au type, single-and double-stacked along the c axis in Pd5InSe and Pd8In2Se, respectively, alternating with [Pd8Se] rectangular prisms. DFT electronic structure calculations predict both compounds to be 3D metallic conductors and Pauli-like paramagnets. According to the bonding analysis based on the electron localization function topology, both compounds feature multi-centered palladium-indium interactions in their heterometallic fragments. (C) 2013 Elsevier B. V. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000330181400008 Publication Date 2013-12-01  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0925-8388; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.133 Times cited 12 Open Access  
  Notes Approved Most recent IF: 3.133; 2014 IF: 2.999  
  Call Number UA @ lucian @ c:irua:114840 Serial 3552  
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Author Batuk, D.; Batuk, M.; Morozov, V.A.; Meert, K.W.; Smet, P.F.; Poelman, D.; Abakumov, A.M.; Hadermann, J. pdf  url
doi  openurl
  Title Effect of cation vacancies on the crystal structure and luminescent properties of Ca(0.85-1.5x)Gd(x)Eu(0.1)_(0.05+0.5x)WO(4) (0<x<0.567) scheelite-based red phosphors Type A1 Journal article
  Year 2017 Publication Journal of alloys and compounds Abbreviated Journal J Alloy Compd  
  Volume 706 Issue 706 Pages 358-369  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract The Ca0.85-1.5xGdxEu0.1_0.05-0.5xWO4 (0 < x < 0.567) series of cation-deficient scheelites is investigated to unveil the influence of the cation vacancies on the crystal structure and luminescent properties. The concentration of the vacancies is varied by the heterovalent substitution of Gd3+ for Ca2+, keeping the concentration of the Eu3+ luminescent centers constant in all compounds of the series. The crystal structure of the materials is studied using a combination of transmission electron microscopy and synchrotron X-ray powder diffraction. At low vacancy concentration (x = 0.1, 0.2), cations and cation vacancies are randomly distributed in the structure, and the materials preserve the I41/a symmetry of the parent scheelite structure [x = 0.1: a = 5.25151(1) Å, c = 11.39479(2) Å; x = 0.2: a = 5.25042(1) Å, c = 11.41335(2) Å]. At higher concentration, the cation-vacancy ordering gives rise to incommensurately modulated structures. The x = 0.3 structure has a (3 + 2)D tetragonal symmetry [superspace group I41/a(a,b,0)00(-b,a,0)00, a = 5.24700(1) Å, c = 11.45514(3) Å, q1 = 0.51637(14)a* + 0.80761(13)b*, q2 = -0.80761a* + 0.51637b*]. At x = 0.4, the scheelite basic cell undergoes a monoclinic distortion with the formation of the (3 + 1)D structure [superspace group I2/b(a,b,0)00, a = 5.23757(1) Å, b = 5.25035(1) Å, c = 11.45750(2) Å, g = 90.5120(2) o, q = 0.54206(8)a* + 0.79330(8)b*]. In both structures, the antiphase Ca and (Gd,Eu) occupancy modulations indicate that the ordering between the A cations and vacancies also induces partial Ca/(Gd,Eu) cation ordering. Further increase of the Gd3þ content up to x = 0.567 leads to the formation of a monoclinic phase (space group C2/c) with the Eu2/3WO4-type structure. Despite the difference in the cation-vacancy ordering patterns, all materials in the series demonstrate very similar quantum efficiency and luminescence decay lifetimes. However, the difference in the local coordination environment of the A cation species noticeably affects the line width and the multiplet splitting of the 4f6-4f6 transitions.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000397997300045 Publication Date 2017-02-16  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0925-8388 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.133 Times cited 2 Open Access OpenAccess  
  Notes This research was supported by FWO (Flanders Research Foundation, project G039211N). V.A.M. is grateful for financial support of the Russian Foundation for Basic Research (Grant 15-03-07741).We are grateful to the ESRF for granting the beamtime at the ID22 beamline and to Andy Fitch for the support during the experiment. Approved Most recent IF: 3.133  
  Call Number EMAT @ emat @ c:irua:142367 Serial 4581  
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Author Chizhov, A.S.; Rumyantseva, M.N.; Vasiliev, R.B.; Filatova, D.G.; Drozdov, K.A.; Krylov, I.V.; Abakumov, A.M.; Gaskov, A.M. doi  openurl
  Title Visible light activated room temperature gas sensors based on nanocrystalline ZnO sensitized with CdSe quantum dots Type A1 Journal article
  Year 2014 Publication Sensors and actuators : B : chemical Abbreviated Journal Sensor Actuat B-Chem  
  Volume 205 Issue Pages 305-312  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract This work reports the study of photoconductivity and visible light activated room temperature gas sensors properties of nanocrystalline ZnO thick films sensitized with colloidal CdSe quantum dots (QDs). Nanocrystalline zinc oxide (ZnO) was synthesized by the precipitation method. Colloidal CdSe quantum dots were obtained by high temperature colloidal synthesis. Sensitization was effectuated by three different procedures including direct adsorption of CdSe QDs stabilized with oleic acid on ZnO surface, anchoring to the ZnO surface through a bifunctional molecule of mercaptopropionic acid (MPA), and coating of CdSe QDs with a monolayer of MPA with subsequent adsorption on ZnO surface. Sensor measurements demonstrated that obtained QD CdSe/ZnO nanocomposites can be used for NO2 detection under visible (green) light illumination at room temperature without any thermal heating. (C) 2014 Elsevier B.V. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Lausanne Editor  
  Language Wos 000343117600041 Publication Date 2014-09-06  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0925-4005; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 5.401 Times cited 36 Open Access  
  Notes Approved Most recent IF: 5.401; 2014 IF: 4.097  
  Call Number UA @ lucian @ c:irua:121107 Serial 3848  
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Author Rumyantseva, M.N.; Vladimirova, S.A.; Vorobyeva, N.A.; Giebelhaus, I.; Mathur, S.; Chizhov, A.S.; Khmelevsky, N.O.; Aksenenko, A.Y.; Kozlovsky, V.F.; Karakulina, O.M.; Hadermann, J.; Abakumov, A.M.; Gaskov, A.M. pdf  url
doi  openurl
  Title p -CoO x / n -SnO 2 nanostructures: New highly selective materials for H 2 S detection Type A1 Journal article
  Year 2017 Publication Sensors and actuators : B : chemical Abbreviated Journal Sensor Actuat B-Chem  
  Volume Issue Pages  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Nanostructures p-CoOx/n-SnO2 based on tin oxide nanowires have been prepared by two step CVD technique and characterized in detail by XRD, XRF, XPS, HAADF-STEM imaging and EDX-STEM mapping. Depending on the temperature of decomposition of cobalt complex during the second step of CVD synthesis of nanostructures cobalt oxide forms a coating and/or isolated nanoparticles on SnO2 nanowire surface. It was found that cobalt presents in +2 and +3 oxidation states. The measurements of gas sensor properties have been carried out during exposure to CO (14 ppm), NH3 (21 ppm), and H2S (2 ppm) in dry air. The opposite trends were observed in the effect of cobalt oxide on the SnO2 gas sensitivity when detecting CO or NH3 in comparison to H2S. The decrease of sensor signal toward CO and NH3 was attributed to high catalytic activity of Co3O4 in oxidation of these gases. Contrary, the significant increase of sensor signal in the presence of H2S was attributed to the formation of metallic cobalt sulfide and removal of the barrier between p-CoOx and n-SnO2. This effect provides an excellent selectivity of p-CoOx/n-SnO2 nanostructures in H2S detection.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000414151800068 Publication Date 2017-08-17  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0925-4005 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 5.401 Times cited 13 Open Access Not_Open_Access: Available from 10.10.2019  
  Notes ERA-Net.Plus, 096 FONSENS ; Approved Most recent IF: 5.401  
  Call Number EMAT @ emat @c:irua:145926 Serial 4710  
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Author Antipov, E.V.; Putilin, S.N.; Shpanchenko, R.V.; Alyoshin, V.A.; Rozova, M.G.; Abakumov, A.M.; Mikhailova, D.A.; Balagurov, A.M.; Lebedev, O.; Van Tendeloo, G. doi  openurl
  Title Structural features, oxygen and fluorine doping in Cu-based superconductors Type A1 Journal article
  Year 1997 Publication Physica: C : superconductivity T2 – International Conference on Materials and Mechanisms of, Superconductivity – High Temperature Superconductors V, Feb. 28-Mar. 04, 1997, Beijing, Peoples R. China Abbreviated Journal Physica C  
  Volume 282 Issue Part 1 Pages 61-64  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract The variation of structures and superconducting properties by changing extra oxygen or fluorine atoms concentration in Hg-based Cu mixed oxides and YBa2Cu3O6+delta was studied. The data obtained by NPD study of Hg-1201 can be considered as an evidence of the conventional oxygen doping mechanism with 2 delta holes per (CuO2) layer. The extra oxygen atom was found to be located in the middle of the Hg mesh only. Different formal charges of oxygen and fluorine inserted into reduced 123 structure results in its distinct variations. The fluorine incorporation into strongly reduced YBa2Cu3O6+delta causes a significant structural rearrangement and the formation of a new compound with a composition close to YBa2Cu3O6F2 (tetragonal alpha = 3.87 Angstrom and c approximate to 13 Angstrom), which structure was deduced from the combined results of X-ray diffraction, electron diffraction and high resolution electron microscopy. Fluorination treatment by XeF2 of nonsuperconducting 123 samples causes an appearance of bulk superconductivity with T-c up to 94K.  
  Address  
  Corporate Author Thesis  
  Publisher Elsevier Science Place of Publication Amsterdam Editor  
  Language Wos A1997XZ90400019 Publication Date 2002-07-25  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0921-4534; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 1.404 Times cited 10 Open Access  
  Notes Approved Most recent IF: 1.404; 1997 IF: 2.199  
  Call Number UA @ lucian @ c:irua:95866 Serial 3237  
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Author Shpanchenko, R.V.; Rozova, M.G.; Abakumov, A.M.; Ardashnikova, E.I.; Kovba, M.L.; Putilin, S.N.; Antipov, E.V.; Lebedev, O.I.; Van Tendeloo, G. openurl 
  Title Inducing superconductivity and structural transformations by fluorination of reduced YBCO Type A1 Journal article
  Year 1997 Publication Physica: C : superconductivity Abbreviated Journal Physica C  
  Volume 280 Issue Pages 272-280  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos A1997XX21600005 Publication Date 0000-00-00  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0921-4534 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 1.404 Times cited 35 Open Access  
  Notes Approved Most recent IF: 1.404; 1997 IF: 2.199  
  Call Number UA @ lucian @ c:irua:21449 Serial 1604  
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Author Corbel, G.; Attfield, J.P.; Hadermann, J.; Abakumov, A.M.; Alekseeva, A.M.; Rozova, M.G.; Antipov, E.V. pdf  doi
openurl 
  Title Anion rearrangements in fluorinated Nd2CuO3.5 Type A1 Journal article
  Year 2003 Publication Chemistry of materials Abbreviated Journal Chem Mater  
  Volume 15 Issue Pages 189-195  
  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 000180368000029 Publication Date 2003-01-07  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 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 Approved Most recent IF: 9.466; 2003 IF: 4.374  
  Call Number UA @ lucian @ c:irua:40348 Serial 123  
Permanent link to this record
 

 
Author Abakumov, A.M.; Batuk, D.; Hadermann, J.; Rozova, M.G.; Sheptyakov, D.V.; Tsirlin, A.A.; Niermann, D.; Waschowski, F.; Hemberger, J.; Van Tendeloo, G.; Antipov, E.V. doi  openurl
  Title Antiferroelectric (Pb,Bi)1-xFe1+xO3-y perovskites modulated by crystallographic shear planes Type A1 Journal article
  Year 2011 Publication Chemistry of materials Abbreviated Journal Chem Mater  
  Volume 23 Issue 2 Pages 255-265  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract We demonstrate for the first time a possibility to vary the anion content in perovskites over a wide range through a long-range-ordered arrangement of crystallographic shear (CS) planes. Anion-deficient perovskites (Pb,Bi)1−xFe1+xO3−y with incommensurately modulated structures were prepared as single phases in the compositional range from Pb0.857Bi0.094Fe1.049O2.572 to Pb0.409Bi0.567Fe1.025O2.796. Using a combination of electron diffraction and high-resolution scanning transmission electron microscopy, we constructed a superspace model describing a periodic arrangement of the CS planes. The model was verified by refinement of the Pb0.64Bi0.32Fe1.04O2.675 crystal structure from neutron powder diffraction data ((3 + 1)D S.G. X2/m(α0γ), X = [1/2,1/2,1/2,1/2], a = 3.9082(1) Å, b = 3.90333(8) Å, c = 4.0900(1) Å, β = 91.936(2)°, q = 0.05013(4)a* + 0.09170(3)c* at T = 700 K, RP = 0.036, RwP = 0.048). The (Pb,Bi)1−xFe1+xO3−y structures consist of perovskite blocks separated by CS planes confined to nearly the (509)p perovskite plane. Along the CS planes, the perovskite blocks are shifted with respect to each other over the 1/2[110]p vector that transforms the corner-sharing connectivity of the FeO6 octahedra in the perovskite framework to an edge-sharing connectivity of the FeO5 pyramids at the CS plane, thus reducing the oxygen content. Variation of the chemical composition in the (Pb,Bi)1−xFe1+xO3−y series occurs mainly because of a changing thickness of the perovskite block between the interfaces, that can be expressed through the components of the q vector as Pb6γ+2αBi1−7γ−αFe1+γ−αO3−3γ−α. The Pb, Bi, and Fe atoms are subjected to strong displacements occurring in antiparallel directions on both sides of the perovskite blocks, resulting in an antiferroelectric-type structure. This is corroborated by the temperature-, frequency-, and field-dependent complex permittivity measurements. Pb0.64Bi0.32Fe1.04O2.675 demonstrates a remarkably high resistivity >0.1 T Ω cm at room temperature and orders antiferromagnetically below TN = 608(10) K.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Washington, D.C. Editor  
  Language Wos 000286160800018 Publication Date 2010-12-23  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 9.466 Times cited 29 Open Access  
  Notes Approved Most recent IF: 9.466; 2011 IF: 7.286  
  Call Number UA @ lucian @ c:irua:88651 Serial 136  
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Author Belik, A.A.; Abakumov, A.M.; Tsirlin, A.A.; Hadermann, J.; Kim, J.; Van Tendeloo, G.; Takayama-Muromachi, E. doi  openurl
  Title Article Structure and magnetic properties of BiFe0.75Mn0.25O3 perovskite prepared at ambient and high pressure Type A1 Journal article
  Year 2011 Publication Chemistry of materials Abbreviated Journal Chem Mater  
  Volume 23 Issue 20 Pages 4505-4514  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Solid solutions of BiFe1xMnxO3 (0.0 ≤ x ≤ 0.4) were prepared at ambient pressure and at 6 GPa. The ambient-pressure (AP) phases crystallize in space group R3c similarly to BiFeO3. The high-pressure (HP) phases crystallize in space group R3c for x = 0.05 and in space group Pnma for 0.15 ≤ x ≤ 0.4. The structure of HP-BiFe0.75Mn0.25O3 was investigated using synchrotron X-ray powder diffraction, electron diffraction, and transmission electron microscopy. HP-BiFe0.75Mn0.25O3 has a PbZrO3-related √2ap × 4ap × 2√2ap (ap is the parameter of the cubic perovskite subcell) superstructure with a = 5.60125(9) Å, b = 15.6610(2) Å, and c = 11.2515(2) Å similar to that of Bi0.82La0.18FeO3. A remarkable feature of this structure is the unconventional octahedral tilt system, with the primary ab0a tilt superimposed on pairwise clockwise and counterclockwise rotations around the b-axis according to the oioi sequence (o stands for out-of-phase tilt, and i stands for in-phase tilt). The (FeMn)O6 octahedra are distorted, with one longer metaloxygen bond (2.222.23 Å) that can be attributed to a compensation for covalent BiO bonding. Such bonding results in the localization of the lone electron pair on Bi3+ cations, as confirmed by electron localization function analysis. The relationship between HP-BiFe0.75Mn0.25O3 and antiferroelectric structures of PbZrO3 and NaNbO3 is discussed. On heating in air, HP-BiFe0.75Mn0.25O3 irreversibly transforms to AP-BiFe0.75Mn0.25O3 starting from about 600 K. Both AP and HP phases undergo an antiferromagnetic ordering at TN ≈ 485 and 520 K, respectively, and develop a weak net magnetic moment at low temperatures. Additionally, ceramic samples of AP-BiFe0.75Mn0.25O3 show a peculiar phenomenon of magnetization reversal.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Washington, D.C. Editor  
  Language Wos 000295897400015 Publication Date 2011-09-29  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 9.466 Times cited 57 Open Access  
  Notes Approved Most recent IF: 9.466; 2011 IF: 7.286  
  Call Number UA @ lucian @ c:irua:93581 Serial 151  
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Author Hadermann, J.; Abakumov, A.M.; Van Rompaey, S.; Mankevich, A.S.; Korsakov, I.E. doi  openurl
  Title Comment on ALaMn2O6-y (A = K, Rb): novel ferromagnetic manganites exhibiting negative giant magnetoresistance Type Editorial
  Year 2009 Publication Chemistry of materials Abbreviated Journal Chem Mater  
  Volume 21 Issue 9 Pages 2000-2001  
  Keywords Editorial; Electron microscopy for materials research (EMAT)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Washington, D.C. Editor  
  Language Wos 000265781000036 Publication Date 2009-04-14  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 9.466 Times cited 4 Open Access  
  Notes Approved Most recent IF: 9.466; 2009 IF: 5.368  
  Call Number UA @ lucian @ c:irua:77055 Serial 411  
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Author Hadermann, J.; Abakumov, A.M.; Gillie, L.J.; Martin, C.; Hervieu, M. pdf  doi
openurl 
  Title Coupled cation and charge ordering in the CaMn306 tunnel structure Type A1 Journal article
  Year 2006 Publication Chemistry of materials Abbreviated Journal Chem Mater  
  Volume 18 Issue 23 Pages 5530-5536  
  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 000241808600021 Publication Date 2006-10-15  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 9.466 Times cited 33 Open Access  
  Notes Iap V-1 Approved Most recent IF: 9.466; 2006 IF: 5.104  
  Call Number UA @ lucian @ c:irua:61374 Serial 534  
Permanent link to this record
 

 
Author Morozov, V.A.; Raskina, M.V.; Lazoryak, B.I.; Meert, K.W.; Korthout, K.; Smet, P.F.; Poelman, D.; Gauquelin, N.; Verbeeck, J.; Abakumov, A.M.; Hadermann, J.; pdf  doi
openurl 
  Title Crystal Structure and Luminescent Properties of R2-xEux(MoO4)(3) (R = Gd, Sm) Red Phosphors Type A1 Journal article
  Year 2014 Publication Chemistry of materials Abbreviated Journal Chem Mater  
  Volume 26 Issue 24 Pages 7124-7136  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract The R-2(MoO4)(3) (R = rare earth elements) molybdates doped with Eu3+ cations are interesting red-emitting materials for display and solid-state lighting applications. The structure and luminescent properties of the R2-xEux(MoO4)(3) (R = Gd, Sm) solid solutions have been investigated as a function of chemical composition and preparation conditions. Monoclinic (alpha) and orthorhombic (beta') R2-xEux(MoO4)(3) (R = Gd, Sm; 0 <= x <= 2) modifications were prepared by solid-state reaction, and their structures were investigated using synchrotron powder X-ray diffraction and transmission electron microscopy. The pure orthorhombic beta'-phases could be synthesized only by quenching from high temperature to room temperature for Gd2-xEux(MoO4)(3) in the Eu3+-rich part (x > 1) and for all Sm2-xEux(MoO4)(3) solid solutions. The transformation from the alpha-phase to the beta'-phase results in a notable increase (similar to 24%) of the unit cell volume for all R2-xEux(MoO4)(3) (R = Sm, Gd) solid solutions. The luminescent properties of all R2-xEux(MoO4)(3) (R = Gd, Sm; 0 <= x <= 2) solid solutions were measured, and their optical properties were related to their structural properties. All R2-xEux(MoO4)(3) (R = Gd, Sm; 0 <= x <= 2) phosphors emit intense red light dominated by the D-5(0)-> F-7(2) transition at similar to 616 nm. However, a change in the multiplet splitting is observed when switching from the monoclinic to the orthorhombic structure, as a consequence of the change in coordination polyhedron of the luminescent ion from RO8 to RO7 for the alpha- and beta'-modification, respectively. The Gd2-xEux(MoO4)(3) solid solutions are the most efficient emitters in the range of 0 < x < 1.5, but their emission intensity is comparable to or even significantly lower than that of Sm2-xEux(MoO4)(3) for higher Eu3+ concentrations (1.5 <= x <= 1.75). Electron energy loss spectroscopy (EELS) measurements revealed the influence of the structure and element content on the number and positions of bands in the ultraviolet-visible-infrared regions of the EELS spectrum.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000347139700027 Publication Date 2014-11-27  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 9.466 Times cited 24 Open Access  
  Notes Fwo G039211n; G004413n; 278510 Vortex ECASJO_; Approved Most recent IF: 9.466; 2014 IF: 8.354  
  Call Number UA @ lucian @ c:irua:122829UA @ admin @ c:irua:122829 Serial 558  
Permanent link to this record
 

 
Author Abakumov, A.M.; Erni, R.; Tsirlin, A.A.; Rossell, M.D.; Batuk, D.; Nénert, G.; Van Tendeloo, G. pdf  doi
openurl 
  Title Frustrated octahedral tilting distortion in the incommensurately modulated Li3xNd2/3-xTiO3 perovskites Type A1 Journal article
  Year 2013 Publication Chemistry of materials Abbreviated Journal Chem Mater  
  Volume 25 Issue 13 Pages 2670-2683  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Perovskite-structured titanates with layered A-site ordering form remarkably complex superstructures. Using transmission electron microscopy, synchrotron X-ray and neutron powder diffraction, and ab initio structure relaxation, we present the structural solution of the incommensurately modulated Li3xNd2/3xTiO3 perovskites (x = 0.05, superspace group Pmmm(α1,1/2,0)000(1/2,β2 0)000, a = 3.831048(5) Å, b = 3.827977(4) Å, c = 7.724356(8) Å, q1 = 0.45131(8)a* + 1/2b*, q2 = 1/2a* + 0.41923(4)b*). In contrast to earlier conjectures on the nanoscale compositional phase separation in these materials, all peculiarities of the superstructure can be understood in terms of displacive modulations related to an intricate octahedral tilting pattern. It involves fragmenting the pattern of the out-of-phase tilted TiO6 octahedra around the a- and b-axes into antiphase domains, superimposed on the pattern of domains with either pronounced or suppressed in-phase tilt component around the c-axis. The octahedral tilting competes with the second order JahnTeller distortion of the TiO6 octahedra. This competition is considered as the primary driving force for the modulated structure. The A cations are suspected to play a role in this modulation affecting it mainly through the tolerance factor and the size variance. The reported crystal structure calls for a revision of the structure models proposed for the family of layered A-site ordered perovskites exhibiting a similar type of modulated structure.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Washington, D.C. Editor  
  Language Wos 000321809700015 Publication Date 2013-06-04  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 9.466 Times cited 23 Open Access  
  Notes Countatoms Approved Most recent IF: 9.466; 2013 IF: 8.535  
  Call Number UA @ lucian @ c:irua:109216 Serial 1292  
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