A5036099365- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Advanced Condensed Matter Physics
- Inorganic Chemistry and Materials
- Solid-state spectroscopy and crystallography
- Ferroelectric and Piezoelectric Materials
- Inorganic Fluorides and Related Compounds
- Advancements in Battery Materials
- Magnetic and transport properties of perovskites and related materials
- Advanced Battery Materials and Technologies
- Nuclear Physics and Applications
- Crystal Structures and Properties
- Microstructure and Mechanical Properties of Steels
- Multiferroics and related materials
- High Temperature Alloys and Creep
- Chemical Synthesis and Characterization
- Microwave Dielectric Ceramics Synthesis
- Nuclear materials and radiation effects
- Rare-earth and actinide compounds
- Nuclear Materials and Properties
- Acoustic Wave Resonator Technologies
- Advanced Materials Characterization Techniques
- Intermetallics and Advanced Alloy Properties
- Methane Hydrates and Related Phenomena
- Luminescence Properties of Advanced Materials
Heinz Maier-Leibnitz Zentrum
2014-2023
Technical University of Munich
2014-2023
Max Planck Computing and Data Facility
2014-2018
University of Edinburgh
2016
TU Wien
2016
Tomsk Polytechnic University
2015
Technical University of Darmstadt
2005-2014
Leipzig University
2013
TU Dresden
2013
Centre National de la Recherche Scientifique
2013
Structural features responsible for lithium conductivity in Li1+xTi2–xAlx(PO4)3 (x = 0, 0.2, and 0.4) samples have been investigated by Rietveld analysis of high-resolution neutron diffraction (ND) patterns. From structural analysis, variation the Li site occupancies atomic thermal factors deduced as a function aluminum doping temperature range 100–500 K. Fourier map differences from ND patterns revealed that ions occupy M1 sites and, to lower extent, M3 sites, disposed around ternary axes....
Novel Cr containing Co-Al-W base superalloys were studied by atom probe tomography and neutron diffraction. is found to predominantly partition the γ matrix decrease partitioning of W γ′. Furthermore, significantly enhances γ′ volume fraction, decreases γ/ lattice misfit deteriorates creep resistance. Addition Ni alloys affects Al, further results in formation irregularly shaped precipitates. tend occupy ‘B'sublattice γ′-A 3 B phase (L1 2 type), while Co reside ‘A’ sublattice.
The phase diagram of the lead-free piezoelectric (1 − x )K 0.5 Na NbO 3 – Bi 1/2 TiO system has been studied by high-resolution synchrotron powder diffraction, neutron diffraction and selected area electron diffraction. two materials K form an infinite substitution solid solution. orthorhombic ( O ), monoclinic M tetragonal T ) rhombohedral R phases coexistence Pm + P 4 mm for 0.02 < ≤ 0.14, bm pseudocubic (Pm{\overline 3}m) 0.14 0.87 c 0.96 have investigated at room temperature, with a...
Combining infrared reflectivity, transport, susceptibility, and several diffraction techniques, we find compelling evidence that CaCrO3 is a rare case of metallic antiferromagnetic transition-metal oxide with three-dimensional electronic structure. Local spin density approximation calculations correctly describe the behavior as well anisotropic magnetic ordering pattern C type: The high Cr valence state induces via sizable pd hybridization remarkably strong next-nearest-neighbor interactions...
The structure of Li4Ti5O12 was investigated by neutron powder diffraction, and the study revealed unprecedented details about lithium migration at high temperatures. A commercial sample battery anode material (spinel-type) measured from room temperature to 1100 °C. Up 500 °C, linearly increasing values for unit cell parameter, isotropic atomic displacement parameters, oxygen position are observed. At 700 a change slope occurs, which is assigned beginning lithium. Previous investigations...
The crystal structure and magnetic of the chromate series $A$CrO${}_{3}$ ($A$ $=$ Ca, Sr, Pb) where Cr exhibits unusual Cr${}^{4+}$ oxidation state have been studied by comprehensive diffraction experiments. In addition we present a detailed analysis infrared optical properties polycrystalline CaCrO${}_{3}$ which is found to be metallic along all crystallographic directions. forms rare case three-dimensional antiferromagnetic transition-metal oxide in occurrence ordering closely coupled...
In this study, the evolution of field induced mechanisms in lead-free piezoelectric ceramics (1−x)Bi1/2Na1/2TiO3-xBaTiO3 with x = 0.06 and 0.07 was investigated by transmission electron microscopy, neutron, X-ray diffraction. Preliminary investigations revealed a strong degradation macroscopic electromechanical properties within first 100 bipolar electric cycles. Therefore, structural investigation focuses on comparative diffraction study freshly prepared, poled, fatigued specimens....
The high resolution powder diffractometer SPODI (jointly operated by the Karlsruhe Institute of Technology and Technische Universität München) is designed for structure solution Rietveld refinement crystal magnetic structural parameters on polycrystalline powders. Instrumental specification (design, flexibility, peak shape, etc.) as well a variety specialized sample environment equipment implemented in-situ materials characterisation make instrument attractive studies complex ordering phenomena.
The nature of the cubic-like state in lead-free piezoelectric ceramics 0.5K0.5Na0.5NbO3-0.5Na0.5Bi0.5TiO3 (KNN-50BNT) has been examined detail by synchrotron x-ray diffraction (SD), selected area electron (SAED), neutron (ND), and temperature dependent dielectric characterization. SD pattern KNN-50BNT presents a pure perovskite structure with pseudocubic symmetry. However, superlattice reflections were observed SAED completely indexed tetragonal symmetry P4bm space group ND pattern. relaxor...
Abstract The structure powder diffractometer SPODI at FRM II is a common project of Darmstadt University Technology, Ludwig-Maximilians Munich, and Technische Universität München. main objectives the instrument are to achieve high Q-resolution provide versatile powerful sample environment. In addition applications high-resolution diffraction determine crystallographic magnetic structures, developed particularly for materials science applications. Prior construction, individual components as...
Li2Ti6O13 and H2Ti6O13 were easily synthesized from Na2Ti6O13 by successive Na+–Li+–H+ ion exchange. The crystal structures of Na2Ti6O13, investigated using neutron powder diffraction. Monovalent A+ cations (Na, Li H) have been located difference Fourier analysis. Although monoclinic lattice parameters (space group C2/m) the three titanates remain almost unchanged with retention basic [Ti6O132−] network, monovalent Na, H occupy different sites in tunnel space. By comparing structural details...
H2V3O8 (HVO) is a promising high-capacity cathode material for lithium-ion batteries (LIBs). It allows reversible two-electron transfer during electrochemical lithium cycling processes, yielding very attractive theoretical capacity of 378 mAh g–1. While an abundant number research works exclusively proved the outstanding storage properties H2V3O8, structural changes intercalation process have not been scrutinized, and crystallographic positions occupied by guest species revealed yet....
Low-temperature α-Ba4Ta2O9 is isostructural with α-Ba4Nb2O9 (Sr4Ru2O9 type), and it undergoes a reconstructive phase transition at approximately the same temperature (1400 K) to γ form that can easily be quenched room temperature. However, forms of two compounds are completely different. Whereas γ-Ba4Nb2O9 represents unique structure type, γ-Ba4Ta2O9 adopts more conventional 6H-perovskite type. The α→γ virtually irreversible in tantalate, unlike niobate, which converted back α by annealing...
Ba4Nb2O9 is shown to have two basic polymorphs: a high-temperature γ phase, which represents an entirely new structure type; and low-temperature α has the rare Sr4Ru2O9 type. The phases are separated by reconstructive phase transition at ∼1370 K, kinetics of sufficiently slow that can easily be quenched room temperature. Below ∼950 both absorb significant amounts water. In case protons from absorbed water occupy ordered positions in structure, giving rise stoichiometric γ-III-Ba4Nb2O9·1/3H2O...
The hexatitanate H2Ti6O13 is obtained by a simple successive Na+/Li+/H+ ion exchange of Na2Ti6O13. crystal structure was solved from both synchrotron and neutron powder diffraction. crystallizes in the monoclinic space group C2/m, with = 14.6702(3) Å; b 3.7447(1) c 9.2594(2) β 96.941(2)°. symmetry [Ti6O13]2− framework preserved during reaction. When compared to positions Na Li Na2Ti6O13 Li2Ti6O13, position proton shifted towards O3 atomic position, where it forms covalent O–H bond. vicinity...
Detection of twelve components in the <sup>6</sup>Li MAS-NMR spectra Li<sub>3</sub>Ti<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> recorded at room temperature suggests location Li<sup>+</sup> ions near different three-oxygen faces that define large M<sub>2</sub> cavities. The occupation M3 and M3′ sites deduced by ND technique has been ascribed to lower spatial resolution achieved experiments.