Pinned magnetization in the antiferromagnet and ferromagnet of an exchange bias system

Using polarized neutron reflectometry, we obtained separate depth profiles for pinned and unpinned magnetization across the interface of a ferromagnet/antiferromagnet bilayer as a function of the sign of exchange bias. The pinned and unpinned magnetization depth profiles are nonuniform and extend well beyond the chemical interface, suggesting an interfacial region magnetically distinct from its surroundings. A model that includes pinned and unpinned moments in the ferromagnet and antiferromagnet is developed for a complete description of the data.