Observation of magnetization rotation during the reversal in Co/CoO exchange-bias multilayers

The magnetization-reversal processes of ferromagnetic Co in [Co/CoO/Au]20 exchange-bias multilayers are studied with polarized neutron reflectometry. The investigations were performed at 300 K, i.e. above the Neel temperature of CoO. We measured the non-spin-flip as well as the spin-flip intensities. Thus, we are able to distinguish between a magnetization rotation and a domain-wall movement. This is essential, in order to compare the obtained results to measurements performed below TN of CoO, when the sample is in the exchange-bias state (i.e. after field cooling).