Temperature stability of Co/Pt and Co/Pd synthetic antiferromagnets using an Ir spacer

Abstract

The magnetic properties of Co/Pt and Co/Pd multilayers of perpendicular synthetic antiferromagnets with an Ir spacer were investigated. A strong interlayer exchange coupling of J_{mathrm{{ex}}}=2.01mathrm{{erg/cm}}^2 was observed in the Co/Pt-based structures and a lower value of J_{mathrm{{ex}}}=1.04mathrm{{erg/cm}}^2 was found in the Co/Pd multilayers. Only the former revealed a high post-annealing stability at T_a=330,^{circ }C, as the latter exhibited a ferromagnetic coupling most likely due to the deterioration of the spacer by pinhole coupling. This assumption was confirmed by theoretical calculations of the total energy functional. Moreover, the high temperature stability of Ir-based Co/Pt p-SAF structures was verified by calculating the exchange field H_{mathrm{{ex}}} from magnetization M(H) loops as a function of temperature, where it reached a temperature of T_b=370,^{circ }C before losing all interlayer exchange coupling.