Effects of Ni on the electrical conductivity and microstructure of La0.82Sr0.16MnO3

The effects of Ni doped into La0.82Sr0.16MnO3 (LSM) have been studied. La0.82Sr0.16Mn1−xNixO3 compositions with Ni content up to x=0.3 have been prepared by the solid state reaction and characterized to investigate the microstructure, thermal expansion coefficient (TEC) and electrical conductivity. A second phase detected by X-ray diffractometry has been found in all compositions after sintering at 1470 °C for 2 h. The results from scanning electron microscope show that the grain sizes of LSM reduce with Ni content and its TEC is changed insignificantly by Ni. The TEC value of 11.7×10−6 K-1 between 100 and 900 °C is obtained for 0⩽x⩽0.3. The electrical conductivity from dc four point measurement indicates a trend of decreasing conductivity with increasing Ni content.