Impact of structural disorder on the magnetic ordering and magnetocaloric response of amorphous Gd-based microwires.

Abstract

We have studied the impact of structural disorder on the magnetic ordering and magnetocaloric response of amorphous Gd 68 Ni 32 and Gd 53 Al 24 Co 20 Zr 3 microwires. We find that the presence of structural disorder significantly broadens the paramagnetic to ferromagnetic (PM-FM) transition and the temperature-dependent magnetic entropy change, while the nature of the second-order magnetic transition and long-range ferromagnetic order are not essentially affected by this effect. The large magnetic moment of Gd and the presence of the long-range ferromagnetic order are believed to result in a large magnetic entropy change, which together with the broadening of the PM-FM transition due to structural disorder contribute to a large refrigerant capacity. The excellent magnetocaloric properties of the amorphous microwires make them very promising candidates for active magnetic refrigeration.