Determination of the anisotropies and reversal process in exchange-bias bilayers using a rotational magnetization curve approach

Rotational magnetization curves of the exchange-bias bilayers were investigated based on the Stoner-Wohlfarth model, which can be grouped into three cases according to the magnetization reversal process. The unidirectional anisotropic field H(E)=41.4 Oe, the uniaxial anisotropic field H(k)=4.2 Oe and the accurate direction of the easy axis of our FeNi/FeMn exchange-bias bilayers were obtained by fitting their experimental rotational magnetization curves. During the rotational process the magnetization reversal of the bilayers is a coherent rotation with a critical magnetization reversal field H(I) = 41.372 Oe. (C) 2010 American Institute of Physics. [doi:10.1063/1.3583664]