MAGNETIC PROPERTY CHANGE OF HIGH PERMEABLE LAYER IN DOUBLE LAYERED PERPENDICULAR MEDIA.

Summary form only given. The authors report on the effects of the Co-Cr layer on the Mo permalloy (MPC) underlayer in double-layer perpendicular recording media. Samples were prepared by RF sputtering, and it was found that the coercivity H//c of the MPC layer was higher than for single MPC films, but that the increase in H//c was lowered as the Cr concentration in the Co-Cr layer increased; this was attributed to magnetic coupling between the Co-Cr and MPC layers. The MPC H//c was also found to depend on the Ar pressure during Co-Cr layer deposition, and on the MPC film thickness. Increases in the MPC H//c can be prevented to some extent by forming a nonmagnetic layer (i. e. , SiO//2 ) between the Co-Cr and MPC.