The exchange bias in ferromagnetic/antiferro-magnetic bilayers under the stress field

Abstract

Using a method in which the free energy is minimized, the exchange bias for ferromagnetic(FM)/antiferromagnetic(AFM) bilayers under the stress field is studied. The thin FM film is considered as a single crystal with cubic and uniaxial magnetocrystalline anisotropies, while the AFM film has only uniaxial magnetocrystalline anisotropy. In the semi-infinite approximation for the AFM layer, the analytical expressions have been derived for effective exchange bias and pinning angle. Numerical calculations show that the effective exchange bias depends on the angle of applied magnetic field, but not on its magnitude. However, the effective exchange bias depends not only on the angle of the stress field but also on its magnitude. The reason is that both the magnitude and angle of the stress field affect the pinning angle.