Effects of component ratio and easy axes distribution on the exchange bias in ferromagnetic–antiferromagnetic random alloys

Abstract

For a ferromagnetic (FM)–antiferromagnetic (AFM) system with composition ( FM ) x + ( AFM ) 1 − x , a modified Monte Carlo Metropolis method is performed to study the effects of x and easy axes distribution at the FM/AFM nearest neighbors on exchange bias field H E, coercivity H C, and vertical magnetization shift M E after cooling under different magnetic fields h CF. When the orientations of easy axes are uniform, the x dependence of H E and M E undergo a non-monotonous to monotonous process with the increase of h CF, whereas H C shows a more complex behavior. On the other hand, for the case of the random orientation, H C has a peak around x = 0.5 , while M E decreases with the increase of x. H E exhibits negative extrema at small x and disappears for larger x. However, abnormal positive H E observed depends on the frustration and the distinct trends of two coercive fields with x in such a special model.