HIGH COERCIVITY IN CO PT MULTILAYERS

We have found that the coercivity was increased when a Co/Pt multilaye r on a Si3N4 underlayer was prepared onto a rotating substrate. A more than twofold increase in the coercivity is thought to be due to the e nhancement of domain wall pinning effects caused by an increase of sur face roughness in the Si3N4 underlayer. According to the results of at omic force microscopy, the surface of the Si3N4 underlayer prepared on to a rotating substrate was rougher than that of an underlayer prepare d onto a stationary substrate. We believe that the enhancement of surf ace roughness is due to the oblique incidence of sputtered materials o n the rotating substrate.