Magnetic and magnetocaloric properties in amorphous and crystalline Tb0.67Au0.33 alloys

The magnetic and magnetocaloric properties of amorphous and crystalline Tb0.67Au0.33 were compared. Amorphous Tb0.67Au0.33 alloy exhibits a spin glass state with a prevailing ferromagnetic behavior with a Curie temperature of 130 K, while the crystalline alloy presents an antiferromagnetic behavior with a Néel temperature of 42 K. Arrott plots show that the amorphous alloy presents a second order magnetic transition while the crystalline state exhibits a field induced a metamagnetic transition. Under magnetic field change of 20 kOe, the maximum magnetic entropy changes were found to be 1.38 and 2.03 J/kg.K, with corresponding relative cooling power of 153 and 40 J/kg for the amorphous and crystalline Tb0.67Au0.33 alloys, respectively.