Interaction between La0.7Sr0.3MnO3 and SrZrO3 in CMR composites

Abstract

Annealing of pressed mechanical mixtures of finely grained La0.7Sr0.3MnO3 and coarse-grained SrZrO3 at T=1000-1300degreesC was accompanied by a systematic decrease in SrZrO3 lattice parameters with increasing La0.7Sr0.3MnO3 : SrZrO3 ratio and a corresponding decrease in sample magnetization at room temperature. EDX nanoprobe analysis of the composites confirmed substantial out-diffusion of La and Mn from La0.7Sr0.3MnO3 into the SrZrO3 particles. This process, detectable at 1100degreesC, leads to an almost Uniform distribution of La and Mn (6-8%) in the SrZrO3 grains and the corresponding changes in manganite particle composition at 1300degreesC. Zr diffusion backflow is almost absent.