Temperature dependence of large exchange-bias in TbFe-Co/Pt

Abstract

The exchange-bias effect provides unidirectional anisotropy to ferromagnetic thin-films in GMR and TMR sensors. It is weak because it relies on an inherently compensated coupling across a ferromagnet/antiferromagnet interface. We replace the antiferromagnet with a TbFe-based perpendicular-anisotropy amorphous ferrimagnet, coupling to an adjacent ferromagnet with 13-5 mJ/m2 for temperatures within 7.9–280 K. A large exchange-bias between 1.1 and 0.7 T in that temperature range ensues. The temperature dependence of the bias is step-like, and thus different from that of antiferromagnet-based exchange-bias systems. It suggests using this material in exchange-biased temperature assisted magnetic writing.