Evaluation of Ni–Mn–In–Si Alloys for Magnetic Refrigerant Application

The influence of excess Ni on the structural, martensitic transformation and magnetic refrigerant properties of Ni_50+xMn_35-xIn₁₄Si₁ (x = 0, 1, and 1.5) alloys was studied by means of X-ray diffraction and magnetization measurements. The martensitic transition temperature increased when Ni was substituted for Mn in Ni_50+xMn_35-xIn₁₄Si₁ and the inverse magnetocaloric effect was observed near the martensitic transformation temperature when the samples were subjected to an applied magnetic field. The maximum magnetic entropy change obtained for the unit magnetic field was 17.2, 19.0, and 2.5 J·kg^-1·K^-1·T^-1 for the alloys with x = 0, 1, and 1.5, respectively. The highest magnetic entropy change obtained was 31.3 J·kg^-1·K^-1 for the alloy with x = 1 at 279 K for a magnetic field change of 0-1.8 T.