Nanoclustering in (Nd0.7Sr0.3)1 − x Mn1 + x O3 ± δ solid solutions

Abstract

The structure of (Nd0.7Sr0.3)1 − x Mn1 + x O3 ± δ solid solutions with x = 0–0.2 (Nd: Sr atomic ratio maintained constant at 2.33) annealed at temperatures from 1200 to 1500°C has been studied by X-ray diffraction. The results demonstrate that, as the annealing temperature is raised, the atomic order in the stoichiometric (x = 0) materials is stable to changes in the homogeneity of the solid solution. In the case of the nonstoichiometric manganites with x = 0.15–0.20, an increase in annealing temperature is accompanied by the development of chemical and topological ordering processes in the matrix structure and cluster growth. The cluster size ranges from 100 to 250 Å, and the largest percentage of clusters (3.5–5.5%) consist of the matrix phase. The fraction of clusters of binary composition, such as MnO-MnO2, is 0.5–2.0%.