Temperature-dependent changes in structural and magnetic properties of heavy ion irradiated nanoscale Co/Pt multilayers

We report the changes in 100?keV Kr ion-irradiated nanoscale Co/Pt multilayers at different temperatures and fluences. We observe irradiation-induced changes in their structural and magnetic properties. Ion beam-induced mixing across the interfaces leads to the formation of a CoPt ordered/disordered phase. A large increase in the coercivity is also observed when the irradiation is performed at room temperature. Such an enhancement in the coercivity is attributed to defect clustering and CoPt ordered/disordered phase formation. The mechanism of phase formation is explained in light of the heat of formation rule.