A5027156048- Inorganic Fluorides and Related Compounds
- Crystal Structures and Properties
- X-ray Diffraction in Crystallography
- Inorganic Chemistry and Materials
- Luminescence Properties of Advanced Materials
- Solid-state spectroscopy and crystallography
- Multiferroics and related materials
- Magnetic properties of thin films
- Advanced Condensed Matter Physics
- Magnetic Properties and Applications
- Electronic and Structural Properties of Oxides
- Magnetism in coordination complexes
- Magnetic Properties and Synthesis of Ferrites
- Advancements in Solid Oxide Fuel Cells
- Chemical Synthesis and Characterization
- Ferroelectric and Piezoelectric Materials
- Methane Hydrates and Related Phenomena
- Atmospheric Ozone and Climate
- Magnetic Properties of Alloys
- Crystallization and Solubility Studies
- Magnetic and transport properties of perovskites and related materials
- Metal and Thin Film Mechanics
- Atmospheric chemistry and aerosols
- Crystal structures of chemical compounds
- Pigment Synthesis and Properties
TU Wien
2007-2016
University of Vienna
2000-2015
AustriaTech (Austria)
2008
University of Geneva
1993-2006
Laboratoire de Chimie de Coordination
1986
Centre National de la Recherche Scientifique
1986
University of Tübingen
1981-1983
A ferroelec. and ferroelastic monodomain single crystal of BiFeO3 at space group R3c is rhombohedral, with a 5.57874(16), c 13.8688(3) .ANG.; arh 5.6343 .ANG., 59.348 Deg; d. (calcd.) = 8.337 for Z 6. Final R 2.4, Rw 1.9% 422 reflections. The structure can be described as rhombohedrally distorted simple cubic perovskite cell. O octahedron min. max. O-O distances 2.710(7) 3.015(9) resp., rotated by about +- 13.8(3) Deg around the 3-fold axis. Fe atom shifted away from center deformed...
Abstract La 0.6 Sr 0.4 CoO 3– δ (LSC) thin‐film electrodes are prepared on yttria‐stabilized zirconia (YSZ) substrates by pulsed laser deposition at different temperatures. The decrease of the film crystallinity, occurring when temperature is lowered, accompanied a strong increase electrochemical oxygen exchange rate LSC. For more or less X‐ray diffraction (XRD)‐amorphous deposited between ca. 340 and 510 °C polarization resistances as low 0.1 Ω cm 2 can be obtained 600 °C. Such films also...
An improved electrode geometry is proposed to study thin ion conducting films by impedance spectroscopy. It shown that long, thin, and closely spaced electrodes arranged interdigitally allow a separation of grain boundary effects also in very films. This be successful for yttria stabilized zirconia (YSZ) layers thinner than 20 nm. In series experiments it demonstrated the extracted parameters correspond YSZ bulk resistances or substrate capacitances. Results show our produced pulsed-laser...
Polycrystalline CoFe2O4 was produced by a ceramic method. The heat-treated powder pressed, varying the hydrostatic pressure between 87 and 278 MPa, again at 1350 °C for 24 h. All magnetic parameters showed clear dependence on this pressure. saturation magnetization minimum, coercivity, anisotropy, magnetostriction maximum compaction pressures around 150 MPa. This of can be explained cation redistribution due to heat treatment. Additionally, all samples were field-annealed in an external...
The crystal structures of cubic and tetragonal NiCr 2 O 4 CuCr have been refined their cell parameters measured, using single-crystal powder X-ray diffraction. It has observed that the differences in Jahn–Teller distortions both compounds are reflected M 2+ –O tetrahedral environments parameters. A calculation atomic shifts during tetragonal–cubic phase transition showed average for oxygen atoms 0.10(1) 0.04(1) Å nickel chromium atoms, respectively. Crystals jump when they go through...
Abstract The room temperature structure of the ferroelastic and presumably ferroelectric Aurivillius type compound Bi5(Ti3Fe)O15 (Mr = 1484.4, Dx 8.065 Mg/m3 Z 4) was refined by X-rays on a weakly twinned crystal prepared in Bi2O3/B2O3 flux with TiO2/Fe2O3 stoichiometrical proportions. lattice constants were found to be orthorhombic 5.4318(6), b 41.149(4) c 5.4691(12)Å. Refinement space group Fmm2 converged at R(Rw). 4.6 (4.2%) 538 averaged reflections. As showed <5% twin domains,...
A comprehensive bulk and surface investigation of high-quality In$_2$O$_3$(001) single crystals is reported. The transparent-yellow, cube-shaped were grown using the flux method. Inductively coupled plasma mass spectrometry (ICP-MS) reveals small residues Pb, Mg, Pt in crystals. Four-point-probe measurements show a resistivity 2.0 $\pm$ 0.5 $\times$ 10$^5$ {\Omega} cm, which translates into carrier concentration $\approx$10$^{12}$ cm$^{-3}$. results from x-ray diffraction (XRD) revise...
Manganese substituted cobalt ferrite, Co1−xMnxFe2O4 (x = 0.0–0.4), was prepared by a ceramic method. The heat-treated powders were pressed at hydrostatic pressure of 167 MPa, and annealed 1350 °C for 24 h. These samples present single-phase cubic spinel structure the compositional mass ratios are close to empirical formula. lattice constant determined from XRD increases with increase Mn content, whereas SEM study reveals that substitution changes microstructure cause pores within grains,...
The oxygen exchange kinetics of platinum on yttria-stabilized zirconia (YSZ) was investigated by means geometrically well-defined Pt microelectrodes. By variation electrode size and temperature it possible to separate two regimes with different geometry dependencies the polarization resistance. At higher temperatures (550–700 °C) an elementary step located close three phase boundary (TPB) activation energy ∼1.6 eV identified as rate limiting. lower (300–400 limiting is related area exhibited...
Thin YSZ films were prepared on magnesia, sapphire and strontium titanate (STO) single crystals using pulsed laser deposition and, for comparison, by a sol-gel method STO. The bulk interfacial mass charge transport properties of these investigated complementary impedance spectroscopy tracer diffusion measurements. In this context, novel two-step experiment is introduced. For grain conductivities similar to those polycrystalline samples measured in most cases. Strongly blocking boundaries...
La-substituted Sr hexaferrite with different La concentrations $x$ were prepared and investigated in order to observe changes magnetic structural properties the substitution. With diffraction methods a change crystal structure below approximately $100\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ from hexagonal spacegroup $P{6}_{3}∕mmc$ orthorhombic $Cmcm$ was observed for fully substituted attributed lattice distortion. A large increase magnetocrystalline anisotropy of...
Abstract Polymeric bis(dimethyl-and diphenylglyoximato)-complexes of Fe(II) and Co(II) with pyrazine as a bridging ligand have been synthesized. The complexes are para-magnetic μ = 1.83 B.M., surprisingly stable against oxidation. Bis (dimethyl-glyoximato)pyrazine-cobalt (II) crystallizes monoclinic in the space group C2/m Z 2. crystal structure shows linear chains alternating Co atoms ligands. Perpendicular to chain, coordinated square planar arrangement by two dimethylglyoximato ligands...
We perform a detailed investigation of the local atomic structure in highly magnetostrictive $\ensuremath{\alpha}\text{-FeGa}$ melt-spun ribbons. By using extended x-ray absorption fine (EXAFS) analysis at Fe and $\text{Ga}\text{ }K$ edges coupled to diffraction (XRD) ab initio full multiple scattering calculations near edge (XANES), we test for presence different defect structures proposed literature as being responsible large magnetostriction these alloys. XRD shows that ribbons...
Across-plane conductivity measurements on ion conducting thin films of a few ten nanometers thickness are challenging due to frequently occurring short-circuits through pinholes in the layer. In this contribution, method is proposed which allowed across-plane yttria stabilized zirconia (YSZ) layers with thicknesses as low 20 nm. YSZ were prepared onto silicon substrates native silica interlayer and was measured circular microelectrodes by impedance spectroscopy. The exhibits strongly...
Abstract From neutron powder diffraction intensities it is often problematic to distinguish between centrosymmetry and non-centrosymmetry. X-ray single crystal may be more accurate. In this paper we compare refinement results of structures on the basis data orthorhombic NdGaO 3 (300 K) rhombohedral LaGaO (573 K), obtained from non-centrosymmetric centrosymmetric starting models. By using measurements, could determined as being corresponding space group R [unk] c Pbnm , respectively.