Thermally assisted oscillatory interlayer exchange bias coupling

Abstract

A strong temperature dependence of the characteristic behavior of the interlayer exchange bias coupling was observed in a ferromagnet/nonmagnetic metal/antiferromagnet trilayer system (NiO/Cu/NiFe). The oscillation of the interlayer exchange bias coupling was found to be thermally assisted. At low temperature, the exchange bias field decreased monotonically with the Cu spacer thickness. Increasing the temperature close to the Ne\'el temperature, the interlayer exchange bias field became oscillatory with the Cu spacer thickness. A simple picture of the temperature-dependent competition between the RKKY-like coupling and the antiferromagnetic coupling within the antiferromagnetic layer as well as the interlayer dipolar interaction is proposed to explain these findings.