Magnetocaloric effect over a temperature span in (Gd x Tb1-x )3Al2 compounds

Abstract

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 x Tb1-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 x Tb1-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 (-ΔSM)max of (Gd x Tb1-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 x Tb1-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, (-ΔSM) and RC suggested that, (Gd x Tb1-x )3Al2 compounds can be used as candidates for magnetic refrigeration.