Structural and high temperature electrical properties of Lay-xSrxMnO3 perovskite materials

The phase constitution of Lay-xSrxMnO3 perovskite materials with 0≤x≤0.4 and 0.8≤y≤1 prepared by wet chemical techniques has been determined. Single phase La-deficient materials have been obtained at y=0.95 and x≥0.1 as well as for y≥0.8 and x≤0.1. The observed variation of the lattice parameters leads to shrinking unit cell volume with Sr-content and with La-deficiency. Small polaron conduction has been observed for x<0.2, while for x≥0.2 metallic-like behaviour is observed for La-deficient materials. The electrical conductivity of Sr-free materials at 950 C approaches 100 S/cm. The activation energy for conduction changes strongly with sintering temperature and composition of the specimen. (orig.)