Richard Henry Ahlert

Crystallographic structure of CoPtCr/CrV thin films as revealed by cross‐section TEM and x‐ray pole‐figure analysis and its relevance to magnetic properties

The crystallographic structure and coercive force of Co75Pt12Cr13/CrVx bilayer films sputter deposited on NiP/AlMg disks used in longitudinal magnetic recording were characterized as a function of varying V content from pure Cr through pure V. The coercive force of the CoPtCr peaked at an intermediate composition of the CrVx sublayer. The origin of this effect was elucidated by x‐ray diffraction, x‐ray pole‐figure analysis, cross‐section TEM, and elongated probe microdiffraction. The improving degree of epitaxy between the CoPtCr and the CrVx sublayer, the increasing fraction of Cr grains favoring the growth of (1120) Co grains with c axis in‐plane, a narrowing of the mosaic spread in the orientation of Co grains, and an increasing size of Co regions with the <1120≳ fiber axis orientation as CrVx composition approaches values between 80/20 and 50/50 Cr/V content account for the observed coercivity increase.

Effect of polycrystalline sublayer films on the magnetic and structural properties of CoCr films

The magnetic and structural properties of Co‐18 at. % Cr films were evaluated for high density longitudinal recording applications. The films exhibited in‐plane magnetization, high coercivity (≲1000 Oe), and hysteresis loop squareness of 0.7–0.89 when the CoCr films were sputtered on sublayer films of Cr or Cr‐20 at. % Co. The coercivity was correlated with the thicknesses of the CoCr film and the sublayer, the deposition conditions, and the percentage of CoCr grains with c‐axis preferred orientation in the film plane.