Preparation, thermal and phase evolution and functional properties of non-stoichiometric strontium-doped lanthanum manganite perovskite ceramics

摘要

Powders of (La0.85Sr0.15)(0.98)MnO3-delta (LSM85) and (La0.80Sr0.20)(0.98)MnO3-delta (LSM80) perovskites have been synthesized and characterized in detail, and then sintered to evaluate their electrical and magnetic properties at low temperatures and at near room temperature. Microstructural observations/analyses after the dilatometric essays show that the perovskites have compositions that deviate from the nominal ones. Furthermore, magnetic characterization of both samples reveals a ferromagnetic behavior with a Curie temperature above 3001< for LSM80 and of 260K for LSM85. In addition, LSM85 is insulator from 15 up to 300 whereas LSM80 is metallic up to 1601(and insulator up to 300 K. This significant discrepancy of behaviour is attributable to structural and compositional differences between the two perovskites. (C) 2017 Elsevier Ltd. All rights reserved.