Epitaxial Growth and Enhanced Saturation Magnetization of Single Crystal Co1–x Crx Media Suitable for Perpendicular Magnetic Recording

Highly c-axis oriented, single crystal films of Co 1– x Cr x have been grown epitaxially on mica substrates by e-beam evaporation. The method, using a Ru underlayer, is simple and applicable to similar c -axis oriented, large area growth of the wide range of Co alloys suitable for perpendicular recording. The films show narrow peak widths in X-ray diffraction (Δ θ (00.2) ~ 1.0–1.5°) and their magnetic properties are composition dependent. Moreover, for any given Cr concentration, these single crystal films exhibit the largest saturation magnetization when compared with either sputtered/evaporated samples or films grown under identical conditions on glass/silicon substrates. It is shown that this enhanced M s is directly correlated with the dispersion of the c -axis about the film normal and their narrowest values are observed for these epitaxially grown films. X-ray microanalysis shows some inter/intra-granular variation in Cr content, but systematic segregation trends appropriate for explaining these results have not yet been observed.