相关论文: Twin model for orthorhombic perovskites

Single crystals of a new twinned hexagonal perovskite compound Sr8Os6.3O24 have been synthesized, and structural and magnetic properties have been determined. The compound crystallizes in a hexagonal cell with lattice parameters a =…

A mathematical framework is developed to describe tilted perovskites using a tensor description of octahedral deformations. The continuity of octahedral tilts through the crystal is described using an operator which relates the deformations…

The structures of the recently reported ordered perovskites SrLa(FeTi)O6 and BaLa(FeTi)O6 have been revisited using Rietveld analysis of the powder x-ray diffraction data. Our studies clearly show that earlier authors have incorrectly…

We study a two-orbital spin model to describe (pi,0) stripe antiferromagnetism in the iron pnictides. The "double-spin" model has an on-site Hunds's coupling and inter-site interactions extending to second neighbors (inter- and…

The dynamics of transformation twins in SrxBa1-xSnO3 (x=0.6,0.8) perovskite has been studied by dynamical mechanical analysis in three-point bend geometry. This material undergoes phase transitions from orthorhombic to tetragonal and cubic…

With recent advances in strain engineering and its widespread applications, it is becoming increasingly important to understand the effect of biaxial strain on the most common structural phase of perovskites -- the orthorhombic $Pnma$…

A crystallographic displacive model is proposed for the extension twins in magnesium. It is based on a hard-sphere assumption previously used for martensitic transformations. The atomic displacements are established, and the homogeneous…

Local and fast structural probes using synchrotron radiation have shown nanoscale striped puddles and nanoscale phase separation in doped perovskites.It is known that the striped phases in doped perovskites are due to competing interactions…

Polycrystalline materials, such as metals, are comprised of heterogeneously oriented crystals. Observed crystal orientations are modelled as a sample from an orientation distribution function (ODF), which determines a variety of material…

With using of point-dipole model the theoretical calculations of main refractive indices and orientation of indicatrix of 18 minerals are performed. The feature of studied minerals is the statistically disordered arrangement of CO3, SO4,…

We report a x-ray resonant diffraction study of the perovskite Pr0.6Ca0.4MnO3. At the Mn K-edge, this technique is sensitive to details of the electronic structure of the Mn atoms. We discuss the resonant x-ray spectra measured above and…

Rotation-reversal symmetry was recently introduced to generalize the symmetry classification of rigid static rotations in crystals such as tilted octahedra in perovskite structures and tilted tetrahedral in silica structures. This operation…

This manuscript presents a working model linking chemical disorder and transport properties in correlated-electron perovskites with high-entropy formulations and a framework to actively design them. We demonstrate this new learning in…

The great variety of lead halide perovskite semiconductors represents an outstanding platform for studying crystal symmetry effects on the spin-dependent properties. Access to them is granted through optical orientation of exciton and…

Ba2MnTeO6 was first characterised using X-ray diffraction and reported to show a small distortion1 from the idealised cubic perovskite which displays face-centred cubic arrangement of Mn2+. A recent report has asserted that this leads to a…

The large amount of powder diffraction data for which the corresponding crystal structures have not yet been identified suggests the existence of numerous undiscovered, physically relevant crystal structure prototypes. In this paper, we…

Neutron diffraction experiments have been carried out on a Sn-flux grown BaFe2As2 single crystal, the parent compound of the A-122 family of FeAs-based high-Tc superconductors. A tetragonal to orthorhombic structural phase transition and a…

It has been long known that numerous halide and oxide perovskites can have non-ideal octahedra, showing tilting, rotation, and metal atom displacements. It has also been known that compounds that have at low temperatures a single structural…

The diffraction peaks of Zircaloy-2 and Zr-2.5%Nb alloys at various deformations are found to be asymmetric in nature. In order to characterize the microstructure from these asymmetric peaks of these deformed alloys, X-Ray Diffraction Line…

We propose a mathematical description of crystal structure: underlying translational periodicity together with the distinct atomic positions up to the symmetry operations in the unit cell. It is consistent with the international table of…