Low-field magnetic entropy change in Dy(Co 1− xSi x) 2

Abstract

A series of Dy(Co 1− x Si x ) 2 ( x=0, 0.01, 0.03, 0.05 and 0.07) compounds have been prepared by arc-melting method. The X-ray diffraction (XRD) analysis reveals that all samples are in the MgCu 2-type structure. The magnetization were measured by a vibrating sample magnetometer (VSM). A first-order transition disappeared by partial substitution of Co by Si ( x>0.05) in the Dy(Co 1− x Si x ) 2 alloys. The magnetic entropy changes (|Δ S M|) as a function of the temperature in magnetic field (1 T) for Dy(Co x Si 1− x ) 2 have been calculated, while the maximum values of |Δ S M are 5.8, 4.1, 3.3, 3.3 and 2.6 J/kg K for x=0, 0.01, 0.03, 0.05 and 0.07, respectively. The Curie temperature ( T C) can be adjusted between 142 and 168 K by partial substitution of Co for Si with some reduction of the |Δ S Max|. The origin of the large magnetocaloric effect (MCE) and the potential application of Dy(Co,Si) 2 as a working material for magnetic refrigerants have also been discussed.