1:3 A-site ordering in perovskite structures: group theoretical analysis

Characterization of Ordering in A-Site Deficient Perovskite Ca1-xLa2x/3TiO3 Using STEM/EELS.

The vacancy ordering behavior of an A-site deficient perovskite system, Ca1-xLa2x/3TiO3, was studied using atomic resolution scanning transmission electron microscopy (STEM) in conjunction with electron energy-loss spectroscopy (EELS), with the aim of determining the role of A-site composition changes. At low La content (x = 0.2), adopting Pbnm symmetry, there was no indication of long-range or...

Structures and phase transitions in perovskites--a group-theoretical approach.

Applications of computer-based group-theoretical methods to perovskite crystallography are reviewed. Such methods furnish a systematic account of the effects on the high-symmetry parent structure of diverse distortions. New results are presented for elpasolites (ordered double perovskites) when both ferroelectric cation displacement and simple octahedral tilting are allowed. Group-theoretical r...

A Group - theoretical Approach to Gabor Analysis

Structures of the cation-deficient perovskite Nd(0.7)Ti(0.9)Al(0.1)O3 from high-resolution neutron powder diffraction in combination with group-theoretical analysis.

The crystal structures of Nd(0.7)Ti(0.9)Al(0.1)O3, taken to represent the ideal Nd(2/3)TiO3, have been elucidated from 4 to 1273 K using high-resolution neutron powder diffraction in combination with group-theoretical analysis. The room-temperature structure is monoclinic in C2/m, on a cell with a = 7.6764 (1), b = 7.6430 (1), c = 7.7114 (1) A, beta = 90.042 (2) degrees . Pertinent features are...

Effect of A-Site Cation Ordering on Chemical Stability, Oxygen Stoichiometry and Electrical Conductivity in Layered LaBaCo2O5+δ Double Perovskite

Abstract: The effect of the A-site cation ordering on the chemical stability, oxygen stoichiometry and electrical conductivity in layered LaBaCo2O5`δ double perovskite was studied as a function of temperature and partial pressure of oxygen. Tetragonal A-site cation ordered layered LaBaCo2O5`δ double perovskite was obtained by annealing cubic A-site cation disordered La0.5Ba0.5CoO3 ́δ perovskite ...