Magnetic properties and large magnetocaloric effect in Gd–Ni amorphous ribbons for magnetic refrigeration applications in intermediate temperature range

Abstract

Amorphous Gd 68− x Ni 32+ x ( x = −3, 0, 3) ribbons were prepared by melt-spinning method. The crystallization onset temperatures T x1 for Gd 68− x Ni 32+ x amorphous ribbons with x = −3, 0, and 3 are 561, 568, and 562 K, respectively. All the samples undergo the second-order magnetic transition at temperatures between ∼122 ( x = −3 and 3) and 124 K ( x = 0). The Curie temperature T C does not change with the composition significantly. The maximum isothermal magnetic entropy changes (−Δ S M) max of Gd 71Ni 29, Gd 68Ni 32, and Gd 65Ni 35 amorphous ribbons for a magnetic field change of 0–5 T were 9.0, 8.0, and 6.9 J kg −1 K −1, respectively. Large values of the refrigerant capacity (RC) were obtained in these ribbons. For example, Gd 71Ni 29 amorphous ribbon has a maximum RC value of 724 J kg −1. Large magnetic entropy change and RC values together with high stability enable the Gd 71Ni 29 amorphous alloy a competitive candidate among the magnetic refrigeration materials working at temperatures near 120 K.