Nanoclustering in (Nd0.7Sr0.3)1-x Mn1+xO3±δ solid solutions

The structure of (Nd0.7Sr0.3)(1 - x) Mn1 + x O-3 +/- delta solid solutions with x = 0-0.2 (Nd: Sr atomic ratio maintained constant at 2.33) annealed at temperatures from 1200 to 1500A degrees 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 , 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%.