Abstract: Cooling field dependence of exchange anisetropy Was investigated in ferromagnetic(FM)/antiferromagnetic(AFM) bilayers with antiferromngnetle interface coupling. It shows that the exchange bias H_E Can change from negative to positive with increasing cooling field H_CF and cooreivity H_C acquires a maximum near crossover of H_E.Especially.effect of FM and AFM thickness on exchange anisotropy is discussed in detail.Both negative(or positive)H_E and H_C always decrease with increasing of FM thickness t_FM,which shows good agreement with experimental observation.It demonstrates interfacial nature of the exchange anisotropy.However,AFM thickness t_AFM dependence of exchange anisotropy is relatively complex.In the case of positive H_E,with increasing of t_FM,H_E increases and H_c decreases.But。in the valse of negative H_E,H_E decreases and H_C increases with increasing t_AFM.

Key words: FM/AFM bilayem, exchange bias, coercivity, cooling field