Magnetocaloric effect over a temperature span in (Gd_xTb_1-x)₃Al₂ compounds

As an environmentally friendly, more efficient and operation-reliable technology, magnetic refrigeration is promised to replace traditional gas compression refrigeration. In our study, we studied the influence on magnetism and magnetocaloric effect of (Gd_xTb_1-x)₃Al₂ (x=0, 0.2, 0.4, 0.6, 0.8, 1) systematically. These results indicated that the increase of Gd concentration increased the lattice constants due to larger atomic radius of Gd atom. Simultaneously, the Curie temperature is dependent on magnetic interaction between Gd atom and Tb atom, and reduced from 279 K to 190 K for x=1 to x=0. Arrott plots indicated that (Gd_xTb_1-x)₃Al₂ compounds showed the characteristics of second-order magnetic phase transition. Under a magnetic field of 0-2 T, the maximum isothermal magnetic entropy (-ΔS_M)^max of (Gd_xTb_1-x)₃Al₂ (x=0, 0.2, 0.4, 0.6, 0.8, 1) compounds are 4.13, 3.79, 3.91, 4.08, 3.96 and 3.98 J/(kg K), respectively. Moreover, refrigeration capacity RC of (Gd_xTb_1-x)₃Al₂ are 59.7, 69.0, 77.6, 65.0, 76.1 and 75.6 J/kg, respective. Adjustable Curie temperature, lower magnetic and thermal hysteresis, (-ΔS_M) and RC suggested that, (Gd_xTb_1-x)₃Al₂ compounds can be used as candidates for magnetic refrigeration.