The structure and magnetic properties of Co-Cr thin films for perpendicular recording

摘要

X-ray analysis, Auger electron spectroscopy (AES), transmission electron microscopy (TEM), and high-voltage transmission electron microscopy (HVTEM) are employed to study the fine structure of a Co-Cr work layer of a multilayer thin-film system for high-density perpendicular magnetic recording. Variations in structure and magnetic properties versus processing parameters are shown. Thin films prepared with optimal technology have a columnar structure with a strong axial texture (c-axis is normal to the film surface) with dispersion up to ≈ 1.5 around the surface normal and in the perpendicular direction. HVTEM studies show that similarly oriented grains are gathered, in the microstructure, into clusters. Precipitates, identified with a micro-microdiffraction method, are found as being of a different character on internal low-angle grain boundaries of clusters than on external ones, which are classified as random grain boundaries. The existence of homogeneous magnetic volumes distinguishable from grain size is brought out using Lorentz microscopy. A correlation between coercivity and cluster size is found.