Magnetocaloric properties of transition metal doped high entropy LaFe11Si2 alloys on Fe sites

Abstract

The working temperature range of magnetic refrigeration (MR) is severely limited by the narrow range of magnetic entropy change (ΔSM) of magnetocaloric (MC) materials, which especially hinders MR applications near room temperature. Here, high-entropy La(Fe, Si)13 based MC materials with increasing number of equimolar transition metal elements such as Mn, Co, Ni, and Cr occupying Fe sites were synthesized using arc melting and annealing, to stabilize the La(Fe, Si)13 phase, and to increase δFWHM. Atomic resolution aberration corrected scanning transmission electron microscopy and elemental mapping confirmed that the doped transition metal elements uniformly occupy the Fe sites. Due to enhanced configuration entropy, the high entropy alloy has achieved La(Fe, Si)13 single phase structure. Magnetic property measurements reveal that the working temperature range of the high entropy alloy has increased by 141.3%. This work provides a new method to design novel MC materials for better stability and larger temperature range.