Grain size reduction in Co/Pd multilayer perpendicular magnetic recording media with NiAl as a seedlayer and a pinning layer

Summary form only given. Co/Pd multilayer films have been extensively studied as perpendicular magnetic recording media. One of the key issues for realizing the high recording densities is to reduce the grain size. The perpendicular magnetic anisotropy for the Co/Pd multilayer films is mainly from the interface magnetic anisotropy, rather than the crystalline magnetic anisotropy for CoCr alloy or FePt perpendicular magnetic recording media. Therefore techniques used for grain size reduction for longitudinal magnetic recording media can also be applied for Co/Pd multilayer perpendicular media. NiAl has been widely used to reduce the grain size for longitudinal magnetic recording media. In this work, NiAl was introduced as a seedlayer for Co/Pd multilayer media and also as a pinning layer into the Co/Pd multilayer media. Co/Pd multilayer films were prepared on glass substrates using DC magnetron sputtering at room temperature. The sputtering Ar gas pressure was 20 mtorr. Magnetic properties were measured with an alternate gradient force magnetometer (AGFM). Film surface structures were observed with atomic force microscopy (AFM).