Influence of Domain Replication on Magnetoresistance of Co/Au/Co Film With Perpendicular Anisotropy and Antiferromagnetic Coupling

The magnetoresistance effect and evolution of the magnetic domain structure were investigated in Co/Au/Co spin-valve structures characterized by perpendicular anisotropy and weak antiferromagnetic coupling. The magnetoresistive minor loops taken with a partially reversed magnetically harder layer show three resistance levels. Two of them correspond to a single-domain state of the magnetically soft layer, and the third one corresponds to duplicated domains with an antiparallel magnetization configuration. The first stage of the reversal process from the single-domain state to the multidomain state is controlled by the nucleation of domains, and the second stage is mainly controlled by domain-wall propagation.