Stacking Faults in Smaller Grain Size Perpendicular Media

The effect of stacking faults (SFs) on the uniaxial magnetocrystalline anisotropy (Ku) of perpendicular magnetic recording media is an important factor when the media grain size becomes smaller. In this study, the relationship between grain size, SFs, and the magnetic properties of the media has been evaluated. It was found that when the SiO₂ content in the Co-alloy granular thin film increases, the grain size and Ku decrease, and the amount of SFs increases. Keeping the same oxide volume fraction and decreasing the magnetic grain size does not further increase the amount of SFs much; however, the Ku value further decreases. This is likely due to the larger volume content of the possible presence of a deadlayer in the outermost shell of the smaller magnetic grains. The measured thermal energy barrier (EB) and intrinsic switching field (H ₀) decrease for smaller grain size media, determined by fitting the DC demagnetization (DCD) measurements with Sharrock´s formula. Improving the structure and microstructure characteristics of the smaller grain size media will be important to obtain good magnetic and thermal properties.