Large Magnetocaloric Effect in Ni-Mn-Ga-Cu Ferromagnetic Shape Memory Alloys

Abstract

Recently, magnetic refrigeration as an alternative to conventional vapor compression cooling has received much concern. Magnetocaloric effect (MCE) is the origin of magnetic refrigeration and it can be characterized by isothermal entropy change ΔS. Ni-Mn-(In,Sn,Sb) metamagnetic shape memory alloys have been proposed as refrigerants in MCE since they display inverse and giant MCE in the vicinity of the martensitic transition temperature [1]. However, in these alloys, the contributions of lattice subsystem and magnetic subsystem play against each other to the total ΔS [2]. This is one of obstacles for Ni-Mn-based alloys for applications.