Systematic studies on three dimensionally ordered liquid crystalline phases of different cubic and tetragonal symmetries are presented. The structures of the phases are determined by reconstruction of the electron density distribution from the X-ray diffraction patterns. The known models for electron densities in cubic structures were used whereas a new theoretical model for the structure of th...

The microstructure and morphology of solid-oxide fuel-cell electrodes are very complex but important because they strongly affect the electrical performance of the cell. In this work the high-resolution X-ray nanotomography technique is applied to reconstruct the three-dimensional microstructure of a (La(0.8)Sr(0.2))(0.95)MnO(3) yttria-stabilized zirconia composite cathode. Some key microstruct...

An Fe/Au monatomic multilayer, consisting of alternating single Fe and Au layers, has been studied by means of the self-consistent full-potential linearized augmented plane wave method. We show by total energy minimization that this artificial thin film is in the tetragonal L10 ordered structure with the ratio of the interlayer spacing to the intralayer lattice constant at 0.865. In this config...

Using high resolution x-ray diffraction (XRD) on high purity powders, we resolved the structure and ab symmetry of the intriguing compound Sr2VO4 from room temperature down to 20 K to an unprecedented level of accuracy. Upon cooling, this set of data unambiguously reveals a second-order phase transition lowering the symmetry from tetragonal to orthorhombic at a temperature Tc2 = 136 K. The obse...

Hematophanite, ideally Pb~FeaOsC1, is tetragonal, space group P4mm, with a = 3'92 and c = 15"3I/~. The crystal structure, which has been refined to an R-factor of 9"t %, may be described as an interlayering of perovskite-like units with a cesium chloride or, alternatively, a nadoritelike unit. The nadorite-like part consists of a double layer of PbO4CI4 distorted square antiprisms. Iron atoms a...

To stabilise ferroelectric-tetragonal phase of BaTiO3, the double-doping of Bi and Mn up to 0.5 mol% was studied. Upon increasing the Bi content in BaTiO3:Mn:Bi, the tetragonal crystal-lattice-constants a and c shrank and elongated, respectively, resulting in an enhancement of tetragonal anisotropy, and the temperature-range of the ferroelectric tetragonal phase expanded. X-ray absorption fine ...

We investigate theoretically ferroelastic domain fractions in a heteroepitaxial bilayer consisting of 001 tetragonal PbZrxTi1−xO3 and 001 rhombohedral PbZr1−xTixO3 on a thick 001 passive substrate as a function of the lattice misfit strain between layers and the substrate. By considering the self-strain in each layer and the indirect elastic interaction between the layers, we provide a numerica...