Tunable Curie temperature in Mn1.15Fe0.85P0.55Si0.45 via lattice engineering by Al addition

Abstract Bulk polycrystalline samples of hexagonal Fe2P-type Al-added Mn1.15Fe0.85P0.55Si0.45 were prepared via a solid-state reaction under controlled heat treatment, and their magnetocaloric properties, including magnetization and entropy change, were investigated. Notably, the Curie temperature, which is directly related to the operating temperature of magnetocaloric materials, could be systematically tuned through Al substitution at Si sites owing to the lattice engineering effect. We found an inverse relationship between the Curie temperature and the ratio of the c-axis lattice constant to a-axis lattice constant, which enables the design of magnetocaloric materials for high-performance magnetic cooling systems.