Interface roughness effects on coercivity and exchange bias

We report model calculations of the hysteresis loops of exchange-coupled ferromagnet/antiferromagnet bilayers with monolayer-scale roughness and show that the loops are affected by the combined effect of the interface field strength, the degree of magnetic roughness and magnetostatic effects. The magnetization reversal may occur via domain-wall nucleation at the edges of monoatomic interface steps or coherent magnetization rotation. A magnetic phase diagram is constructed for a 10-nm-thick Fe film, subjected to nanometer-scale interface roughness.