The Effects of Post-Annealing on the Microstructure and Magnetic Properties of Percolated Perpendicular Media

In this paper the effects of post-deposition annealing on the microstructure and magnetic properties of Co-Pt-SiO₂ percolated perpendicular media (PPM) have been examined. Co-Pt-SiO₂ perpendicular thin films were grown on a Ru underlayer by an alternating sputtering method at room temperature. The as-deposited microstructure is similar to that of Co-alloy/oxide granular media. Desired PPM microstructure was obtained upon post-deposition annealing. The as-deposited films have a low coercivity, whereas high coercivity was found after they were annealed. Transmission electron microscopy investigations indicated that the microstructure of the media did not change much after annealing at temperatures of 600 degC or lower. The desired microstructure and thus good magnetic properties occured after about 5 min at 650 degC. When the annealing temperature is greater than 650 degC and/or the annealing time is longer than 10 min, the SiO ₂ pinning sites become larger and less dense