Effect of bilayer repeats on magnetic properties of Au-buffered Co/Ni multilayers with perpendicular magnetic anisotropy

Abstract The effect of bilayer repeats (N) on the static and dynamic magnetic properties of Co/Ni multilayers was investigated. The effective perpendicular magnetic anisotropy constant of multilayers drops from 1.08 × 10 6 erg/cm3 to 0.78 × 10 6 erg/cm3 with N increasing from 5 to 11. For Co/Ni multilayers with N ≤ 7 , sharp magnetization switching was observed. In contrast, Co/Ni multilayers with N ≥ 9 have a long tail in the hysteresis loop. Ferromagnetic resonance measurements show that intrinsic Gilbert damping changes from 0.021 to 0.016 with increase in N and is inversely proportional to N. This study provides a deep understanding and effective control of magnetic properties of Co/Ni multilayers for spintronics devices.