Co/Pd multilayers for perpendicular magnetic recording media

Co/Pd multilayered media were improved using a three-fold approach. InSn seedlayers were used for higher coercivities, the Pd layers were doped with Si to decrease exchange between grains, and the Pd thickness was decreased to increase magnetization. When InSn seedlayers were used for these Co/Pd multilayered perpendicular magnetic recording media, the coercivity increased to measured values of 12.5 kOe and projected values of almost 20 kOe. These large values were obtained even though the depositions described here were done at room temperature. In order to lessen intergranular exchange coupling, Si (which has no solid solubility in Pd) was used to dope the Pd layers. Si also slightly decreased the grain size distribution to 23%. Initial recording measurements showed excellent signal to noise ratios, although an excessively wide switching field distribution prevented recording at the highest densities. Finally, the thickness of the Pd bilayers was reduced to increase the magnetization of the samples from 180 to 300 emu/cm3.