The structure dependence of exchange bias in ferromagnetic / antiferromagnetic bilayers

Abstract

The structure dependence of exchange bias in ferromagnetic/antiferromagnetic (FM/AF) bilayers has been investigated in detail by extending Slonczewski's 'proximity magnetism' idea. Here three important parameters are discussed for FM/AF bilayers, i.e. interfacial bilinear exchange coupling J 1 , interfacial biquadratic (spin-flop) exchange coupling J 2 and antiferromagnetic layer thickness t AF . The results show that both the occurrence and the variety of the exchange bias strongly depend on the above parameters. More importantly, the small spin-flop exchange coupling may result in an exchange bias without the interfacial bilinear exchange coupling. However, in general, the spin-flop exchange coupling cannot result in the exchange bias. The corresponding critical parameters in which the exchange bias will occur or approach saturation are also presented.