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“Influence of Mono- and Bimetallic PtOx, PdOx, PtPdOx Clusters on CO Sensing by SnO2 Based Gas Sensors”. Kutukov P, Rumyantseva M, Krivetskiy V, Filatova D, Batuk M, Hadermann J, Khmelevsky N, Aksenenko A, Gaskov A, Nanomaterials 8, 917 (2018). http://doi.org/10.3390/nano8110917
Abstract: To obtain a nanocrystalline SnO2 matrix and mono- and bimetallic nanocomposites SnO2/Pd, SnO2/Pt, and SnO2/PtPd, a flame spray pyrolysis with subsequent impregnation was used. The materials were characterized using X-ray diffraction (XRD), a single-point BET method, transmission electron microscopy (TEM), and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) with energy dispersive X-ray (EDX) mapping. The electronic state of the metals in mono- and bimetallic clusters was determined using X-ray photoelectron spectroscopy (XPS). The active surface sites were investigated using the Fourier Transform infrared spectroscopy (FTIR) and thermo-programmed reduction with hydrogen (TPR-H-2) methods. The sensor response of blank SnO2 and nanocomposites had a carbon monoxide (CO) level of 6.7 ppm and was determined in the temperature range 60-300 degrees C in dry (Relative Humidity (RH) = 0%) and humid (RH = 20%) air. The sensor properties of the mono- and bimetallic nanocomposites were analyzed on the basis of information on the electronic state, the distribution of modifiers in SnO2 matrix, and active surface centers. For SnO2/PtPd, the combined effect of the modifiers on the electrophysical properties of SnO2 explained the inversion of sensor response from n- to p-types observed in dry conditions.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 3.553
Times cited: 7
DOI: 10.3390/nano8110917
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“Antiferroelectric properties and site occupations ofR3+ cations in Ca8MgR(PO4)7 luminescent host materials”. Belik AA, Morozov VA, Deyneko DV, Savon AE, Baryshnikova OV, Zhukovskaya ES, Dorbakov NG, Katsuya Y, Tanaka M, Stefanovich SY, Hadermann J, Lazoryak BI, Journal of alloys and compounds 699, 928 (2017). http://doi.org/10.1016/J.JALLCOM.2016.12.288
Abstract: Ca8MgR(PO4)(7) = La, Pr, Nd, Sm-Lu, and Y) phosphates with a beta-Ca-3(PO4)(2) related structure were prepared by a standard solid-state method in air. Second-harmonic generation, differential scanning calorimetry, and dielectric measurements led to the conclusion that all Ca8MgR(PO4)(7) are centrosymmetric and go to another centrosymmetric phase in the course of a first-order antiferroelectric phase transition well above room temperature (RT). High-temperature electron diffraction showed that the symmetry changes from R (3) over barc to R (3) over barm during the phase transition. Structures of Ca8MgR(PO4)(7) at RT were refined by the Rietveld method in centrosymmetric space group R (3) over barc. Mg2+ cations occupy the M5 site; the occupancy of the M1 site by R3+ cations increases monotonically from 0.0389 for R = La to 0.1667 for R = Er-Lu, whereas the occupancy of the M3 site by R3+ cations decreases monotonically from 0.1278 for R = La to 0 for R = Er-Lu. In the case of R = Er-Lu, the M3 site is occupied only by Ca2+ cations. P1O(4) tetrahedra and cations at the M3 site are disordered in the R (3) over barc structure of Ca8MgEu(PO4)(7). Using synchrotron X-ray powder diffraction, we found that annealing conditions do not significantly affect the distribution of Ca2+ and Eu3+ cations between the structure positions of Ca8MgEu(PO4)(7). Luminescent properties of CasMgEu(PO4)(7) powder samples were investigated under near-ultraviolet (n-UV) light. Excitation spectra of CasMgEu(PO4)(7) show the strongest absorption at about 395 nm that matches with commercially available n-UV-emitting GaN-based LED chips. Emission spectra show an intense red emission due to the D-5(0) -> F-7(2) transition of Eu3+. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
DOI: 10.1016/J.JALLCOM.2016.12.288
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“Crystal Structure, Defects, Magnetic and Dielectric Properties of the Layered Bi3n+1Ti7Fe3n-3,O9n+11 Perovskite-Anatase lntergrowths”. Batuk D, Batuk M, Filimonov DS, Zakharov KV, Volkova OS, Vasiliev AN, Tyablikov OA, Hadermann J, Abakumov AM, Inorganic chemistry 56, 931 (2017). http://doi.org/10.1021/ACS.INORGCHEM.6B02559
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.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 3
DOI: 10.1021/ACS.INORGCHEM.6B02559
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“Energy transfer in Eu3+ doped scheelites : use as thermographic phosphor”. Meert KW, Morozov VA, Abakumov AM, Hadermann J, Poelman D, Smet PF, Optics express 22, A961 (2014). http://doi.org/10.1364/OE.22.00A961
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.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.307
Times cited: 47
DOI: 10.1364/OE.22.00A961
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“A novel red Ca8.5Pb0.5Eu(PO4)7 phosphor for light emitting diodes application”. Deyneko DV, Morozov VA, Hadermann J, Savon AE, Spassky DA, Stefanovich SY, Belik AA, Lazoryak BI, Journal of alloys and compounds 647, 965 (2015). http://doi.org/10.1016/j.jallcom.2015.06.123
Abstract: Ca9-xPbxEu(PO4)(7) (0 <= x <= 1) solid solutions with a whitlockite-type (or beta-Ca-3(PO4)(2)-type) structure (sp.gr. R3c) were prepared by a standard solid-state method in air. Their luminescent properties under near-ultraviolet (n-UV) light were investigated. Excitation spectra of Ca9-xPbxEu(PO4)(7) showed the strongest absorption at about 395 nm, which matches well with commercially available n-UV-emitting GaN-based LED chips. Emission spectra indicated an intense red emission due to the D-5(0) -> F-7(2) transition of Eu3+, with a maximum in the intensity for Ca8.5Pb0.5Eu(PO4)(7). The emission intensity of Ca8.5Pb0.5Eu(PO4)(7) was about 1.8 times higher than that of a Ca9Eu(PO4)(7) phosphor. We suggest that the introduction of Pb2+ is an efficient approach to enhance luminescence properties of such phosphors. We clarified the influence of the Ca2+/Pb2+ substitution on intensities of three bands for the D-5(0) -> F-7(0) transition in excitation spectra of Ca9-xPbxEu(PO4)(7). In addition, we found a reversible first-order phase transition from R3c to R (3) over barc symmetry by second-harmonic generation in the range from 753 K (x = 1) to 846 K (x = 0). (C) 2015 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.133
Times cited: 18
DOI: 10.1016/j.jallcom.2015.06.123
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“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”. Paria Sena R, Babaryk AA, Khainakov S, Garcia-Granda S, Slobodyanik NS, Van Tendeloo G, Abakumov AM, Hadermann J, Journal of the Chemical Society : Dalton transactions 45, 973 (2016). http://doi.org/10.1039/c5dt03479e
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.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.029
Times cited: 6
DOI: 10.1039/c5dt03479e
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“Effect of Bimetallic Pd/Pt Clusters on the Sensing Properties of Nanocrystalline SnO2 in the Detection of CO”. Malkov I V, Krivetskii VV, Potemkin D I, Zadesenets A V, Batuk MM, Hadermann J, Marikutsa A V, Rumyantseva MN, Gas'kov AM, Russian journal of inorganic chemistry 63, 1007 (2018). http://doi.org/10.1134/S0036023618080168
Abstract: Nanocrystalline tin dioxide modified by Pd and Pt clusters or by bimetallic PdPt nanoparticles was synthesized. Distribution of the modifers on the SnO2 surface was studied by high-resolution transmission electron microscopy and energy dispersive X-ray microanalysis with element distribution mapping. It was shown that the Pd/Pt ratio in bimetallic particles varies over a broad range and does not depend on the particle diameter. The effect of platinum metals on the reducibility of nanocrystalline SnO2 by hydrogen was determined. The sensing properties of the resulting materials towards 6.7 ppm CO in air were estimated in situ by electrical conductivity measurements. The sensor response of SnO2 modified with bimetallic PdPt particles was a superposition of the signals of samples with Pt and Pd clusters.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.787
Times cited: 3
DOI: 10.1134/S0036023618080168
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“Mg1-xRhB, a new boridometallide with 2D polyanion”. Alekseeva AM, Abakumov AM, Leithe-Jasper A, Schnelle W, Prots Y, Hadermann J, Van Tendeloo G, Antipov EV, Grin Y, Zeitschrift für anorganische und allgemeine Chemie 631, 1047 (2005). http://doi.org/10.1002/zaac.200400479
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.144
Times cited: 13
DOI: 10.1002/zaac.200400479
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“Crystal structure, polymorphism, and properties of the new vanadyl phosphate Na4VO(PO4)2”. Panin RV, Shpanchenko RV, Mironov AV, Velikodny YA, Antipov EV, Hadermann J, Tarnopolsky VA, Yaroslavtsev AB, Kaul EE, Geibel C, Chemistry of materials 16, 1048 (2004). http://doi.org/10.1021/cm0351543
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 11
DOI: 10.1021/cm0351543
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“Hole doping and structural transformation in CsTl1-xHgxCl3”. Retuerto M, Yin Z, Emge TJ, Stephens PW, Li MR, Sarkar T, Croft MC, Ignatov A, Yuan Z, Zhang SJ, Jin C, Paria Sena R, Hadermann J, Kotliar G, Greenblatt M;, Inorganic chemistry 54, 1066 (2015). http://doi.org/10.1021/ic502400d
Abstract: CsTlCl3 and CsTlF3 perovskites have been theoretically predicted to be superconductors when properly hole-doped. Both compounds have been previously prepared as pure compounds: CsTlCl3 in a tetragonal (I4/m) and a cubic (Fm3̅m) perovskite polymorph and CsTlF3 as a cubic perovskite (Fm3̅m). In this work, substitution of Tl in CsTlCl3 with Hg is reported, in an attempt to hole-dope the system and induce superconductivity. The whole series CsTl1xHgxCl3 (x = 0.0, 0.1, 0.2, 0.4, 0.6, and 0.8) was prepared. CsTl0.9Hg0.1Cl3 is tetragonal as the more stable phase of CsTlCl3. However, CsTl0.8Hg0.2Cl3 is already cubic with the space group Fm3̅m and with two different positions for Tl+ and Tl3+. For x = 0.4 and 0.5, solid solutions could not be formed. For x ≥ 0.6, the samples are primitive cubic perovskites with one crystallographic position for Tl+, Tl3+, and Hg2+. All of the samples formed are insulating, and there is no signature of superconductivity. X-ray absorption spectroscopy indicates that all of the samples have a mixed-valence state of Tl+ and Tl3+. Raman spectroscopy shows the presence of the active TlClTl stretching mode over the whole series and the intensity of the TlClHg mode increases with increasing Hg content. First-principle calculations confirmed that the phases are insulators in their ground state and that Hg is not a good dopant in the search for superconductivity in this system.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 5
DOI: 10.1021/ic502400d
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“Synthesis, cation ordering, and magnetic properties of the (Sb1-xPbx)2(Mn1-ySby)O4 solid solutions with the Sb2MnO4-type structure”. Abakumov AM, Rozova MG, Antipov EV, Hadermann J, Van Tendeloo G, Lobanov MV, Greenblatt M, Croft M, Tsiper EV, Llobet A, Lokshin KA, Zhao Y, Chemistry of materials 17, 1123 (2005). http://doi.org/10.1021/cm048791h
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 16
DOI: 10.1021/cm048791h
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“P-N Junction Passivation in Kesterite Solar Cells by Use of Solution-Processed TiO2 Layer”. Ranjbar S, Hadipour A, Vermang B, Batuk M, Hadermann J, Garud S, Sahayaraj S, Meuris M, Brammertz G, da Cunha AF, Poortmans J, IEEE journal of photovoltaics 7, 1130 (2017). http://doi.org/10.1109/JPHOTOV.2017.2692208
Abstract: In this work, we used a solution-processed TiO2 layer between Cu2ZnSnSe4 and CdS buffer layer to reduce the recombination at the p–n junction. Introducing the TiO2 layer showed a positive impact on VOC but fill factor and efficiency decreased. Using a KCN treatment, we could create openings in the TiO2 layer, as confirmed by transmission electron microscopy measurements. Formation of these openings in the TiO2 layer led to the improvement of the short-circuit current, fill factor, and the efficiency of the modified solar cells.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.712
Times cited: 2
DOI: 10.1109/JPHOTOV.2017.2692208
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“Synthesis and magnetic properties of rare earth ruthenates, Ln5Ru2O12 (Ln=Pr, Nd, SmTb)”. Bharathy M, Gemmill WR, Fox AH, Darriet J, Smith MD, Hadermann J, Remy MS, zur Loye H-C, Journal of solid state chemistry 182, 1164 (2009). http://doi.org/10.1016/j.jssc.2009.02.013
Abstract: Single crystals of Ln5Ru2O12 (Ln=Pr, Nd, SmTb) were grown out of either NaOH or KOH fluxes in sealed silver tubes. The crystals of all the phases were observed to be twinned as confirmed by TEM studies. The series crystallize in the C2/m monoclinic system with lattice parameters, a=12.4049(4)12.7621(6) Å, b=5.8414(2)5.9488(3) Å, c=7.3489(2)7.6424(4) Å, β=107.425(3)107.432(2)° and Z=2. The crystal structure is isotypic with the defect/disorder model of Ln5Re2O12 (Ln = Y, Gd) and consists of one dimensional edge shared RuO6 octahedral chains separated by a two dimensional LnOx polyhedral framework. Magnetic measurements indicate paramagnetic and antiferromagnetic behavior for Ln=Nd, SmGd and Ln=Tb, respectively.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 4
DOI: 10.1016/j.jssc.2009.02.013
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“[SrF0.8(OH)0.2]2.526[Mn6O12]: columnar rock-salt fragments inside the todorokite-type tunnel structure”. Abakumov AM, Hadermann J, Van Tendeloo G, Kovba ML, Skolis YY, Mudretsova SN, Antipov EV, Volkova OS, Vasiliev AN, Tristan N, Klingeler R, Büchner B, Chemistry of materials 19, 1181 (2007). http://doi.org/10.1021/cm062508s
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 9
DOI: 10.1021/cm062508s
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“Bi(3n+1)Ti7Fe(3n-3)O(9n+11) Homologous Series: Slicing Perovskite Structure with Planar Interfaces Containing Anatase-like Chains”. Batuk D, Tsirlin AA, Filimonov DS, Zakharov KV, Volkova OS, Vasiliev A, Hadermann J, Abakumov AM, Inorganic chemistry 55, 1245 (2016). http://doi.org/10.1021/acs.inorgchem.5b02465
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.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 3
DOI: 10.1021/acs.inorgchem.5b02465
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“Mechanical synthesis of high purity Cu-In-Se alloy nanopowder as precursor for printed CISe thin film solar cells”. Zaghi AE, Buffière M, Brammertz G, Batuk M, Lenaers N, Kniknie B, Hadermann J, Meuris M, Poortmans J, Vleugels J, Advanced powder technology 25, 1254 (2014). http://doi.org/10.1016/j.apt.2014.03.003
Abstract: Mechanical alloying and ball milling are low cost, up-scalable techniques for the preparation of high purity chalcogenide nanopowders to be used as precursor material for printing thin film solar cells. In this study, high purity copper indium selenium (Cu-In-Se) alloy nanopowders with 20-200 nm particle size were synthesized from macroscopic elemental Cu, In and Se powders via mechanical alloying and planetary ball milling. The particle size distribution, morphology, composition, and purity level of the synthesized Cu-In-Se alloy nanopowders were investigated. Thin Cu-In-Se alloy nanopowder ink coatings, deposited on Mo-coated glass substrates by doctor blading, were converted into a CuInSe2 semiconductor film by selenization heat treatment in Se vapor. The CuInSe2 film showed semiconducting band gap around 1 eV measured by photoluminescence spectroscopy. CuInSe2 absorber layer based thin film solar cell devices were fabricated to assess their performance. The solar cell device showed a total efficiency of 4.8%, as measured on 0.25 cm(2) area cell. (c) 2014 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.659
Times cited: 10
DOI: 10.1016/j.apt.2014.03.003
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“Recent Advances in Transmission Electron Microscopy for Materials Science at the EMAT Lab of the University of Antwerp”. Guzzinati G, Altantzis T, Batuk M, De Backer A, Lumbeeck G, Samaee V, Batuk D, Idrissi H, Hadermann J, Van Aert S, Schryvers D, Verbeeck J, Bals S, Materials 11, 1304 (2018). http://doi.org/10.3390/ma11081304
Abstract: The rapid progress in materials science that enables the design of materials down to the nanoscale also demands characterization techniques able to analyze the materials down to the same scale, such as transmission electron microscopy. As Belgium’s foremost electron microscopy group, among the largest in the world, EMAT is continuously contributing to the development of TEM techniques, such as high-resolution imaging, diffraction, electron tomography, and spectroscopies, with an emphasis on quantification and reproducibility, as well as employing TEM methodology at the highest level to solve real-world materials science problems. The lab’s recent contributions are presented here together with specific case studies in order to highlight the usefulness of TEM to the advancement of materials science.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.654
Times cited: 15
DOI: 10.3390/ma11081304
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“Synthesis and characterization of La1+xSr2-xCoMnO7-\delta (x=0,0.2, \delta=0,1)”. El Shinawi H, Bertha A, Hadermann J, Herranz T, Santos B, Marco JF, Berry FJ, Greaves C, Journal of solid state chemistry 183, 1347 (2010). http://doi.org/10.1016/j.jssc.2010.04.018
Abstract: The n=2 Ruddlesden-Popper phases LaSr(2)CoMnO(7) and La(1 2)Sr(1 8)CoMnO(7) have been synthesized by a sol-gel method The O6-type phases LaSr(2)CoMnO(6) and La(1 2)Sr(1 8)CoMnO(6) were produced by reduction of the 07 phases under a hydrogen atmosphere The materials crystallize in the tetragonal I4/mmm space group with no evidence of long-range cation order in the neutron and electron diffraction data Oxygen vacancies in the reduced materials are located primarily at the common apex of the double perovskite layers giving rise to square pyramidal coordination around cobalt and manganese ions. The oxidation states Co(3+)/Mn(4+) and Co(2+)/Mn(3+) predominate in the as-prepared and reduced materials, respectively The materials are spin glasses at low temperature and the dominant magnetic interactions change from ferro- to antiferromagnetic following reduction (C) 2010 Elsevier Inc All rights reserved
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 5
DOI: 10.1016/j.jssc.2010.04.018
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“Local oxygen-vacancy ordering and twinned octahedral tilting pattern in the Bi0.81Pb0.19FeO2.905 cubic perovskite”. Dachraoui W, Hadermann J, Abakumov AM, Tsirlin AA, Batuk D, Glazyrin K, McCammon C, Dubrovinsky L, Van Tendeloo G, Chemistry of materials 24, 1378 (2012). http://doi.org/10.1021/cm300178x
Abstract: The structure of Bi0.81Pb0.19FeO2.905 was investigated on different length scales using a combination of electron diffraction, high-resolution scanning transmission electron microscopy, synchrotron X-ray powder diffraction, and Mössbauer spectroscopy. In the 80300 K temperature range, the average crystal structure of Bi0.81Pb0.19FeO2.905 is a cubic Pm3̅m perovskite with a = 3.95368(3) Å at T = 300 K. The (Pb2+, Bi3+) cations and O2 anions are randomly displaced along the 110 cubic directions, indicating the steric activity of the lone pair on the Pb2+ and Bi3+ cations and a tilting distortion of the perovskite framework. The charge imbalance induced by the heterovalent Bi3+ → Pb2+ substitution is compensated by the formation of oxygen vacancies preserving the trivalent state of the Fe cations. On a short scale, oxygen vacancies are located in anion-deficient (FeO1.25) layers that are approximately 6 perovskite unit cells apart and transform every sixth layer of the FeO6 octahedra into a layer with a 1:1 mixture of corner-sharing FeO4 tetrahedra and FeO5 tetragonal pyramids. The anion-deficient layers act as twin planes for the octahedral tilting pattern of adjacent perovskite blocks. They effectively randomize the octahedral tilting and prevent the cooperative distortion of the perovskite framework. The disorder in the anion sublattice impedes cooperative interactions of the local dipoles induced by the off-center displacements of the Pb and Bi cations. Magnetic susceptibility measurements evidence the antiferromagnetic ordering in Bi0.81Pb0.19FeO2.905 at low temperatures.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 27
DOI: 10.1021/cm300178x
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“Oxygen and fluorine doping in Sr2MnGaO5 brownmillerite”. Antipov EV, Abakumov AM, Alekseeva AM, Rozova MG, Hadermann J, Lebedev OI, Van Tendeloo G, Physica status solidi: A: applied research 201, 1403 (2004). http://doi.org/10.1002/pssa.200304428
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 9
DOI: 10.1002/pssa.200304428
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“Structures and magnetism of La1-xSrxMnO3-(0.5+x)/2 (0.67\leq x\leq1) phases”. Dixon E, Hadermann J, Hayward MA, Chemistry of materials 24, 1486 (2012). http://doi.org/10.1021/cm300199b
Abstract: Topotactic reduction of La1-xSrxMnO3 (0.67 <= x <= 1) phases with sodium hydride yields a series of isoelectronic materials of composition La1-xSrxMnO3-(0.5+x)/2. Lanthanum rich members of the series (0.67 <= x <= 0.83) adopt anion deficient perovskite structures with a 6-layer -OTOOT'O- stacking sequence of sheets of octahedra/square-based pyramids (O) and sheets of tetrahedra (T). The strontium rich members of the series (0.83 <= x <= 1) incorporate “step defects” into this 6-layer structure in which the OTOOT'O stacking sequence is converted into either OOTOOT' or TOOT'OO at a defect plane which runs perpendicular to the [201] lattice plane. The step defects appear to provide a mechanism to relieve lattice strain and accommodate additional anion deficiency in phases with x > 0.83. Magnetization and neutron diffraction data indicate La1-xSrxMnO3-(0.5+x)/2 phases adopt antiferromagnetically ordered states at low-temperature in which the ordered arrangement of magnetic spins is incommensurate with the crystallographic lattice.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 13
DOI: 10.1021/cm300199b
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“New lead vanadium phosphate with langbeinite-type structure: Pb1.5V2(PO4)3”. Shpanchenko RV, Lapshina OA, Antipov EV, Hadermann J, Kaul EE, Geibel C, Materials research bulletin 40, 1569 (2005). http://doi.org/10.1016/j.materresbull.2005.04.037
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.446
Times cited: 14
DOI: 10.1016/j.materresbull.2005.04.037
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“Fluorine intercalation in the n=1 and n=2 layered manganites Sr2MnO3.5+x and Sr3Mn2O6”. Sullivan E, Gillie LJ, Hadermann J, Greaves C, Materials research bulletin 48, 1598 (2013). http://doi.org/10.1016/j.materresbull.2012.12.073
Abstract: Fluorine insertion into the oxygen defect superstructure manganite Sr2MnO3.5+x has been shown by transmission electron microscopy (TEM) to result in two levels of fluorination. In the higher fluorine content sections, the fluorine anions displace oxygen anions from their apical positions into the equatorial vacancies, thus destroying the superstructure and reverting to a K2NiF4-type structure (a = 3.8210(1) angstrom and c = 12.686(1) angstrom). Conversely, lower fluorine content sections retain the Sr2MnO3.5+x defect superstructure, crystallising in the P2(1)/c space group. Fluorine intercalation into the reduced double-layer manganite Sr3Mn2O6 occurs in a step-wise fashion according to the general formula Sr3Mn2O6Fy with y = 1, 2, and 3. It is proposed that the y = 1 phase (a = 3.815(1)angstrom, c = 20.29(2) angstrom) is produced by the filling of all the equatorial oxygen vacancies by fluorine atoms whilst the y = 2 phase (a = 3.8222(2) angstrom, c = 21.2435(3)angstrom) has a random distribution of fluorine anions throughout both interstitial rocksalt and equatorial sites. Neutron powder diffraction data suggest that the fully fluorinated y = 3 phase (a = 3.8157(6) angstrom, c = 23.666(4) angstrom) corresponds to the complete occupation of all the equatorial oxygen vacancies and the interstitial sites by intercalated fluorine. (C) 2013 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.446
Times cited: 4
DOI: 10.1016/j.materresbull.2012.12.073
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“Engineered spatial inversion symmetry breaking in an oxide heterostructure built from isosymmetric room-temperature magnetically ordered components”. Alaria J, Borisov P, Dyer MS, Manning TD, Lepadatu S, Cain MG, Mishina ED, Sherstyuk NE, Ilyin NA, Hadermann J, Lederman D, Claridge JB, Rosseinsky MJ;, Chemical science 5, 1599 (2014). http://doi.org/10.1039/c3sc53248h
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 8.668
Times cited: 24
DOI: 10.1039/c3sc53248h
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“Structural requirements in lithium cobalt oxides for the catalytic oxidation of water”. Gardner GP, Go YB, Robinson DM, Smith PF, Hadermann J, Abakumov A, Greenblatt M, Dismukes GC, Angewandte Chemie: international edition in English 51, 1616 (2012). http://doi.org/10.1002/anie.201107625
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 11.994
Times cited: 119
DOI: 10.1002/anie.201107625
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“Synthesis and charactreization of the new Ln(2)FeMoO(7) (Ln = Y, Dy, Ho) compounds”. Veith GM, Lobanov MV, Emge TJ, Greenblatt M, Croft M, Stowasser F, Hadermann J, Van Tendeloo G, Journal of materials chemistry 14, 1623 (2004). http://doi.org/10.1039/b315028c
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 17
DOI: 10.1039/b315028c
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“Study of hydrogen peroxide reactions on manganese oxides as a tool to decode the oxygen reduction reaction mechanism”. Ryabova AS, Bonnefont A, Zagrebin P, Poux T, Sena RP, Hadermann J, Abakumov AM, Kerangueven G, Istomin SY, Antipov EV, Tsirlina GA, Savinova ER, ChemElectroChem 3, 1667 (2016). http://doi.org/10.1002/CELC.201600236
Abstract: Hydrogen peroxide has been detected as a reaction intermediate in the electrochemical oxygen reduction reaction (ORR) on transition-metal oxides and other electrode materials. In this work, we studied the electrocatalytic and catalytic reactions of hydrogen peroxide on a set of Mn oxides, Mn2O3, MnOOH, LaMnO3, MnO2, and Mn3O4, that adopt different crystal structures to shed light on the mechanism of the ORR on these materials. We then combined experiment with kinetic modeling with the objective to correlate the differences in the ORR activity to the kinetics of the elementary reaction steps, and we uncovered the importance of structural and compositional factors in the catalytic activity of the Mn oxides. We concluded that the exceptional activity of Mn2O3 in the ORR is due to its high catalytic activity both in the reduction of oxygen to hydrogen peroxide and in the decomposition of the latter, and furthermore, we proposed a tentative link between crystal structure and reactivity.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.136
Times cited: 20
DOI: 10.1002/CELC.201600236
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“Nanoscale Characterization of Growth of Secondary Phases in Off-Stoichiometric CZTS Thin Films”. Vishwakarma M, Karakulina OM, Abakumov AM, Hadermann J, Mehta BR, Journal of nanoscience and nanotechnology 18, 1688 (2018). http://doi.org/10.1166/jnn.2018.14261
Abstract: The presence of secondary phases is one of the main issues that hinder the growth of pure kesterite Cu2ZnSnS4 (CZTS) based thin films with suitable electronic and junction properties for efficient solar cell devices. In this work, CZTS thin films with varied Zn and Sn content have been prepared by RF-power controlled co-sputtering deposition using Cu, ZnS and SnS targets and a subsequent sulphurization step. Detailed TEM investigations show that the film shows a layered structure with the majority of the top layer being the kesterite phase. Depending on the initial thin film composition, either about ~1 μm Cu-rich and Zn-poor kesterite or stoichiometric CZTS is formed as top layer. X-ray diffraction, Raman spectroscopy and transmission electron microscopy reveal the presence of Cu2−x S, ZnS and SnO2 minor secondary phases in the form of nanoinclusions or nanoparticles or intermediate layers.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 1.483
DOI: 10.1166/jnn.2018.14261
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“Novel, oxygen-deficient n=3 RP-member Sr3NdFe3O9-\delta and its topotactic derivatives”. Pelloquin D, Hadermann J, Giot M, Caignaert V, Michel C, Hervieu M, Raveau B, Chemistry of materials 16, 1715 (2004). http://doi.org/10.1021/cm030351n
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 24
DOI: 10.1021/cm030351n
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“Crystal structure and properties of the Na1-xRu2O4 phase”. Panin RV, Khasanova NR, Abakumov AM, Schnelle W, Hadermann J, Antipov EV, Russian chemical bulletin 55, 1717 (2006). http://doi.org/10.1007/s11172-006-0478-6
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.529
Times cited: 5
DOI: 10.1007/s11172-006-0478-6
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