Magnetoelastic coupling induced magnetocaloric property variations in Ni-doped (Mn, Fe)2(P, Si) alloys

This study investigated MnFe0.95-xNixP0.5-ySi0.5+y (0.01 <= x <= 0.16, -0.05 <= y <= 0.1) alloys prepared by arc melting. The alloys were crystallized in a typical Fe2P-type hexagonal main phase. They exhibited strong coupling between lattice variation and magnetic transition, which is the major factor in the large magne-tocaloric properties. The effects of coupling were observed from two perspectives: Fe-Ni substitution for transition temperature tuning and P/Si ratio for reducing the amount of expensive P alloy. For the Fe -Ni substitution, the transition temperature decreased by about 7.8 K per 0.01 Ni contents (x). In the case of the P/Si ratio control, a secondary phase was generated based on the increase in Si content. The alloys showed maximum magnetic entropy change ( increment delta S-M(max)) ranging from 8.65 to 17.22 J kg(-1) K-1 for the applied magnetic field 2 T in the temperature range from 214 K to 335 K. For the MnFe(0.91)Ni(0.04)P(0.45)Si(0.55 )alloy with a low P/Si ratio, the increment delta S(M)(max )was 15.32 J kg(-1) K-1 for the applied magnetic field 2 T at 304 K close to room temperature. This demonstrates that the alloys with large magnetocaloric properties in this research are competitive to other known magnetic refrigeration materials. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study investigates the properties of MnFe0.95-xNixP0.5-ySi0.5+y alloys prepared by arc melting. The alloys exhibit strong coupling between lattice variation and magnetic transition, which contributes to their large magnetocaloric properties. The transition temperature can be tuned through Fe-Ni substitution, and the amount of expensive P alloy can be reduced by controlling the P/Si ratio. The alloys show a maximum magnetic entropy change in the temperature range from 214 K to 335 K under an applied magnetic field of 2 T. The alloy with a low P/Si ratio demonstrates competitive magnetocaloric properties to other known magnetic refrigeration materials.