Induced magnetic moments at a ferromagnet-antiferromagnet interface

We have studied the magnetization depth profile in a Co/LaFeO₃ exchange bias system with polarized neutron reflectometry. In the exchange biased state we observe differences between the reflectivity profiles when the magnetization of the ferromagnetic layer is saturated either parallel or antiparallel to the cooling field. This difference vanishes above the blocking temperature. Since the reflectivity profiles are directly related to the Fourier components of the magnetization depth profile, this data suggest that a net moment develops within the antiferromagnetic layer close to the interface with the ferromagnetic layer, which remains unchanged during the magnetic-field cycling and is coupled antiferromagnetically to the ferromagnet.