Variation of structural, magnetic and transport properties in RE0.7Sr0.3MnO3 granular perovskites

Granular perovskite family RE0.7Sr0.3MnO3 (RE = rare earth except Ce and Sc ) were prepared by thermal decomposition of complex precursors. The effects of A-site rare earth elements on structural symmetry, magnetic and transpo rt properties were systematically investigated. While RE is varied from La to Lu, the perovskite structure is distorted from rhombohedral to orthorhom bic and finally to hexagonal symmetry for small rare earths. Meanwhile, the magnetic measurement shows a variation corresponding to the phase transiti on. Carrier mobility and magnetoresistance also strongly depend on the rare earth elements. Our results reveal that the tolerance factor r plays an im portant role in the structural distortion and grain boundary effect for the granular compounds. In addition, the band-bending effects are suggested to explain the discrepancy in the transport properties of this family. (C) 20 01 Elsevier Science Ltd. All rights reserved.