Analysis of microstructures for Co/Pd multilayer perpendicular magnetic recording media with carbon underlayer

The effect of amorphous carbon underlayer thickness on the microstructure of the CO/Pd multilayer perpendicular magnetic recording media was investigated. From the magnetic force microscopy observation in the AC-demagnetized state of the Co/Pd multilayer media, the magnetic cluster size was observed to effectively decrease with an increase in carbon underlayer thickness, where the higher coercivity and the higher SIN ratio of the Co/Pd multilayer media were obtained with the thicker underlayer. Furthermore, the distribution of [111] orientation of FCC-Pd became broader, and the grain size decreased with an increase in the carbon underlayer thickness. These effects caused the magnetic exchange decoupling of Co/Pd multilayer media. We suggested that the change of microstructure was directly related to the surface roughness of the amorphous carbon underlayer. (C) 2001 Elsevier Science B.V. All rights reserved.