Magnetic properties of CoTb/FePt(001) nano-bilayer films

The magnetic properties and microstructure of CoTb/FePt bilayer films are investigated. The magnetic anisotropy of the Co₇₀Tb₃₀/FePt(001) film is perpendicular to the film plane. The saturated magnetization (M_s) and perpendicular coercivity (H_{\mathrm {c} \bot } ) of the Co₇₀Tb₃₀/FePt(001) bilayer films are higher than those of single-layered Co₇₀Tb₃₀ films. The H_{\mathrm {c} \bot } and M_s are 5450 Oe, and 403 emu cm^-3, respectively. As the temperature is increased to 200 °C, there is a rapid decrease in the H_{\mathrm {c} \bot } value.