Correlation of micromagnetic structure and microstructure in thin film longitudinal magnetic recording media

Abstract

Lorentz transmission electron microscopy (LTEM) has long been used as a tool for imaging the magnetic domain structure in materials and has occasionally been applied to thin film longitudinal magnetic recording media. Conventional/high-resolution electron microscopy (TEM) has shown its power in revealing the detailed microstructure of these materials. The combination of these two techniques can result in a more complete understanding of the interdependence of micromagnetic structure and microstructure and provide insight into how to improve the magnetic performance.LTEM requires specimens with large uniformly thin areas so that the deflection angle of the incident electron beam is proportional to the magnetic field within the specimen plane. Conventional specimen preparation methods, which normally generate a wedge, are therefore no longer suitable. Previous work has used specially designed substrates to facilitate preparation of LTEM specimens of Co alloy/Cr magnetic media. In the present study a chemical etching technique was introduced to successfully produce LTEM specimens directly from the C/Co alloy/Cr/NiP/Al(substrate) structures, typical of those currently used in the magnetic disk industry.