Controllable ferromagnetic/re-entrant spin glass state and magnetocaloric response of Gd-Er-Al-Co metallic glasses

Abstract The effects of random anisotropy on the magnetic transition and magnetic entropy change (MEC) have been investigated in a series of Gd-Er-Al-Co metallic glasses(MGs) through Er addition. The Gd-based metallic glass without Er shows typical ferromagnetic transition. With Er addition, the Curie temperature decreases and a re-entrant spin glass like behavior can be observed due to the frustration among random magnetic anisotropy (RMA) and exchange interactions. A large maximum MEC of 9.1 J kg −1 K −1 around 117.5 K is obtained in Gd 56 Co 24 Al 20 MG, which can be tuned continuously in a wide temperature range (117.5–17.5 K) by introducing Er without impairing the good glass forming ability. A largest peak MEC of 12.6 J kg −1 K −1 has been obtained around 17.5 K in Gd 8 Er 48 Co 24 Al 20 . Significantly, the exponent n of field dependence of MEC is found to depend on the degree of magnetic frustration among RMA and exchange interactions.