Effect of Cu spacer on the perpendicular magnetic remanence and Mrt-product of Co/Ni multilayers

Abstract

Multiple multilayer structures composed of Co/Ni multilayers separated by Cu spacer layers, having perpendicular magnetic anisotropy, were prepared by UHV vapor deposition. By decreasing the Co/Ni multilayer thickness and increasing the Cu spacer thickness, the perpendicular remanence at a constant total Co/Ni thickness of 1200 Å was enhanced to about 90% of the saturation value, while an M r t-product exceeding 60 mA was reached. The enlarged remanence is due to an increased coercivity, and a decreased saturation field as predicted by the domain theory for multilayers. The spacering effect is of importance in perpendicular magnetic recording and in applications where a strong perpendicular field is required to penetrate an adjacent device material.