Anomalous magnetic and electrical properties of disordered double perovskite alloy LaCaMnFeO6

Abstract

Double perovskite alloys are of significant interest owing to their intriguing magnetic properties and potential practical applications. In this study, we provided a detailed report on the structural, electrical and magnetic features of the double perovskite LaCaMnFeO _6 , prepared via the conventional solid-state reaction technique. Neutron diffraction analysis showed that the sample is single-phase adopting the Pnma orthorhombic structure with random distribution of La ^3+ /Ca ^2+ and Mn ^4+ /Fe ^3+ ions on A- and B-sites, respectively. A long-range G-type antiferromagnetic order was formed below T _N = 250 K. Magnetic measurements unveiled a cluster glassy behavior at low temperatures with a complex distribution of cluster magnetic anisotropy energy. Ferromagnetic clusters consisting of two Mn ^4+ and one Fe ^3+ were found to exist in the paramagnetic phase. The complex magnetic properties of LaCaMnFeO _6 are attributed to the cation disorder effect combined with the competition between magnetic interactions. Unusual electrical behavior with a large positive magnetoresistive effect was observed and correlated to magnetic phase transitions.

Keywords

• magnetism
• phase transition
• crystal structure
• double perovskite alloy