EFFECT OF CU SPACERS ON THE PERPENDICULAR MAGNETIC REMANENCE AND M(R)T-PRODUCT OF CO NI MULTILAYERS/

Multiple multilayer structures composed of Co/Ni multilayers separated by Cu spacer layers, having perpendicular magnetic anisotropy, were p repared by UHV vapor deposition. By decreasing the Co/Ni multilayer th ickness and increasing the Cu spacer thickness, the perpendicular rema nence at a constant total Co/Ni thickness of 1200 angstrom was enhance d to about 90% of the saturation value, while an M(r)t-product exceedi ng 60 mA was reached. The enlarged remanence is due to an increased co ercivity, and a decreased saturation field as predicted by the domain theory for multilayers. The spacering effect is of importance in perpe ndicular magnetic recording and in applications where a strong perpend icular field is required to penetrate an adjacent device material.