Rotational relaxation of pinning field in AFM/FM bilayer films

Rotational relaxation of the pinning field was studied in PtMn/CoFe and IrMn/CoFe exchange coupled bilayer films using a vector vibrating sample magnetometer (VVSM). The measurement allows determination of the pinning field direction and magnitude as well as the easy axis direction. The experimental results can be explained using the model of thermally activated switching of AFM grains taking into account the distribution of the activation energies of the grains, in-plane exchange in the FM layer, and the difference in the origin of the uniaxial anisotropy