Tuning the exchange bias training effect in top- and bottom-pinning FeNi/FeMn bilayers

Abstract

A magnetic field of 600 Oe, different from the original pinning direction (PD), is applied in the film plane to tune the exchange bias (EB) training effect in both top- and bottom-pinning FeNi/FeMn bilayers. Compared to the top-pinning structures, the training effects in the bottom-pinning ones are more easily tuned, characterized by larger rotation of the PD just after the field tuning. The EB tuning effect is thought to be originated from spin frustration near the FM/AF interface, and the interfacial AF spins are less stable and readily to be tuned by external field in the bottom-pinning bilayers than those in the top-pinning bilayers. This statement can also be validated by the azimuthal dependence of the EB effect. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.