Antiferromagnetically coupled hard/Ru/soft layers and their applications in spin valves

Abstract

Antiferromagnetically coupled hard/Ru/soft triple layers have been fabricated using ultrahigh vacuum sputtering. A series of experiments has been carried out to study the dependence of the exchange-coupling field on the thickness of the soft layer which is either CoFe or NiFe, while the hard layer is CoCrPt. It was found that this type of synthetic structure exhibits a significantly higher exchange coupling field as compared to the conventional antiferromagnet/ferromagnet exchange coupled structures. The use of these synthetic structures as the pinned and pinning layers has resulted in spin valves with a magnetoresistance ratio in the range of 5%-7% and a thermal stability that is better than those of IrMn-based and comparable to those of PtMn-based spin valves. © 2002 American Institute of Physics.