Field dependence of magnetization for a thin ferromagnetic film on rough antiferromagnetic surface

•The FM/AFM layered systems with rough interfaces are studied theoretically.•The magnetization curves M(H) of FM/AFM bilayer are shifted along the field axis.•The hysteresis loops shape depend on the FM/AFM interface roughness degree.•A few percents of the uncompensated interface spins are enough for exchange bias.•M(H) curves for the perfect and rough interfaces may be qualitatively the same.

Simple theoretical models are proposed for the analytical and the numerical study of the exchange bias phenomenon in the layered systems with rough AFM/FM interface. It is shown that the qualitative type of the magnetization curves depend crucially on the variation of the roughness degree. We obtain that the magnetization curves are qualitatively of the same type in the cases of perfect and rough FM/AFM interfaces. The method which allow to identify the character of the interface (rough or perfect) is proposed.