Masaki Ohura

Magnetic properties and read/write characteristics of Co‐Cr‐(Pt,Ta)/ (Cr‐Ti,Cr) thin film media

A Cr‐Ti underlayer is found to enhance the in‐plane coercive forces of Co‐Cr‐Pt and Co‐Cr‐Ta films; the maximum coercive force was 3.5 kOe for (CoCr0.15)0.84Pt0.16/CrTi0.2. The crystallites of Cr‐Ti grow in a more highly oriented and uniform manner than ones of Cr, and their lattice spacings are closer to those of Co alloys than Cr, improving the epitaxial growth of Co‐alloy crystallites with c‐axis in‐plane oriented components on the Cr‐Ti underlayer. The crystalline anisotropy constant of Co‐Cr‐Pt with a high Pt concentration is found by torque measurement to be larger than that of Co‐Cr‐Ta. These can produce extremely high coercive forces in Co‐Cr‐Pt/Cr‐Ti. The C/Co‐Cr‐Pt/Cr‐Ti thin film media with high coercive forces show excellent read/write characteristics; the linear densities at 50% signal drop are very high, 175 and 101 kFCI, for the C/Co‐Cr‐Pt/Cr‐Ti media at head‐to‐magnetic layer spacings of 0.01 and 0.07 μm.