Enhanced magnetocaloric effect in Ni-Mn-Sn-Co alloys with two successive magnetostructural transformations

Xuexi Zhang; Hehe Zhang; Mingfang Qian; Lin Geng

doi:10.1038/s41598-018-26564-5

Enhanced magnetocaloric effect in Ni-Mn-Sn-Co alloys with two successive magnetostructural transformations

Sci Rep. 2018 May 29;8(1):8235. doi: 10.1038/s41598-018-26564-5.

Authors

Xuexi Zhang¹, Hehe Zhang², Mingfang Qian², Lin Geng²

Affiliations

¹ School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China. xxzhang@hit.edu.cn.
² School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China.

Abstract

High magnetocaloric refrigeration performance requires large magnetic entropy change ΔS _M and broad working temperature span ΔT _FWHM . A fourth element doping of Co in ternary Ni-Mn-Sn alloy may significantly enhance the saturation magnetization of the alloy and thus enhance the ΔS _M . Here, the effects of Co-doping on the martensite transformation, magnetic properties and magnetocaloric effects (MCE) of quaternary Ni_47-xMn₄₃Sn₁₀Co_x (x = 0, 6, 11) alloys were investigated. The martensite transformation temperatures decrease while austenite Curie point increases with Co content increasing to x = 6 and 11, thus broadening the temperature window for a high magnetization austenite (13.5, 91.7 and 109.1 A·m²/kg for x = 0, 6 and 11, respectively). Two successive magnetostructural transformations (A → 10 M and A → 10 M + 6 M) occur in the alloy x = 6, which are responsible for the giant magnetic entropy change ΔS _{M =} 29.5 J/kg·K, wide working temperature span ΔT _FWHM = 14 K and large effective refrigeration capacity RC _eff = 232 J/kg under a magnetic field of 5.0 T. These results suggest that Ni_40.6Mn_43.3Sn_10.0Co_6.1 alloy may act as a potential solid-state magnetic refrigerant working at room temperature.