Tunable thermal hysteresis in MnFe(P,Ge) compounds

TLDR

The study proposes an effective approach to produce ideal magnetic refrigerants for room‑temperature applications. The authors systematically investigated the structural, magnetic, and magnetocaloric properties of MnFe(P,Ge) bulk alloys and melt‑spun ribbons. The phase‑transition critical behavior can be tuned by composition or annealing, enabling very small thermal hysteresis while preserving a large magnetocaloric effect across a wide temperature range and field changes achievable with conventional permanent magnets.

Abstract

Structural, magnetic, and magnetocaloric properties of the MnFe(P,Ge) compounds were systematically studied on both bulk alloys and melt-spun ribbons. The experimental results show that the critical behavior of the phase transition can be controlled by changing either the compositions or the annealing conditions. The thermal hysteresis is found to be tunable. It can reach very small values, while maintaining a large magnetocaloric effect in a large range of working temperatures and under field changes that may be produced by conventional permanent magnets. Consequently, an effective way in producing ideal magnetic refrigerants for room-temperature applications is suggested.