Magnetocaloric and Refrigeration Characteristics of Magnetic Composite Material Composed with Gd and Gd 1-x Ho x Alloy

The doping of Ho into Gd can not only adjust the Curie temperature of Gd1-xHox alloy but also enhance the maximal magnetic entropy change. In the present paper, the magnetocaloric characteristics of Gd1-xHox alloys were calculated by means of the de Gennes model, and the isothermal magnetic entropy change of Gd1-xHox (x = 0, 0.05, 0.10, 0.15, 0.20) alloys versus temperature curves generally exhibit a caret-like shape. Furthermore, the composite material composed of Gd and Gd0.80Ho0.20 is introduced in order to obtain a gentler entropy change curve over a large temperature span. Consequently, it is found under magnetic field change from 0 to 2 T that the composite composed of Gd and Gd0.80Ho0.20 with 67% mass ratio of Gd possesses a maximal full width at half maxima δTFWHM of the isothermal magnetic entropy change curve which is 87.3 K, with temperature 217.9 K of the cold end at half-width and temperature 305.2 K of the hot end at half-width. In such a case, the maximal magnetic entropy change is 4.17 J/(kgK), relative cooling power (RCP) is about 360 J/kg, and refrigeration capacity (RC) achieves 280.6 J/kg. The results show that the composite magnetocaloric material can largely enhance the material performance for magnetic refrigeration application.