Magnetic effect and chemical distribution study of LCMNO3 perovskite by photoelectron spectroscopy

Abstract

Abstract The crystal structure, x-ray photoemission spectroscopy, magnetic characteristics, and magnetocaloric performance of perovskite La0.55Ca0.45Mn0.8Nb0.2O3 (LCMNO) ceramic powder were analyzed. The orthorhombic structure with a Pnma space group was found as the main phase in the as-received compound after the XRD pattern refinement. The mixed-valence states of manganese were detected by x-ray photoemission spectroscopy (XPS). The analysis of the La3d line revealed the complex nature of the lanthanum states. The evaluation of Zero-Field-Cooled and Field-Cooled magnetization performance provided conclusive evidence for the existence of the antiferromagnetic Mn3O4 phase at a temperature of TN = 42 K and the coexistence of CO- AFM and FM domains in LCMNO. Despite the observed significant (δTFWHM) value due to relatively low magnetic entropy change (ΔSM), the relative cooling power (RCP) is relatively moderate. By adding Nb4+, the changes in Mn valences and their effect on the magnetic cooling effect are lessened.