Effect of metallic additives (M) on the exchange coupling of antiferromagnetic CrMnMx films to a ferromagnetic Ni81Fe19 film

Among metal additives M(M:Pt, Pd, Rh, Ir, and Cu) of antiferromagnetic ${\mathrm{CrMnM}}_x$ films, Pd was the most suitable M for obtaining large exchange coupling. For the 50 nm ${\mathrm{CrMnPd}}_{\mathrm{5}}\mathrm{/40\hspace{0.17em}nm}$ ${\mathrm{Ni}}_{\mathrm{81}}{\mathrm{Fe}}_{\mathrm{19}}$ films, the exchange coupling field of $\text{∼28\hspace{0.17em}}\mathrm{Oe}$ and the blocking temperature of $\text{∼380\hspace{0.17em}}\mathrm{°C}$ could be obtained. The ${\mathrm{CrMn(Pt,\hspace{0.17em}Pd,\hspace{0.17em}or\hspace{0.17em}Rh)}}_x$ films having the optimum content of $\text{∼8,}$ $\text{∼5,}$ or $\text{∼11}$ at.% exhibited the same high blocking temperature. The high blocking temperature of the ${\mathrm{CrMnPt}}_{\mathrm{8}},$ ${\mathrm{CrMnPd}}_{\mathrm{5}},$ and ${\mathrm{CrMnRh}}_{\mathrm{11}}$ films was attributed to the nearest neighbor Mn–Mn within the respective films being at the same distance as that at which the Mn–Mn exchange integral showed the maximum negative value.