Perpendicular Magnetic Recording Media on Various Hard-Disk Substrates
Co-Cr perpendicular media on rigid substrates were studied. We used untextured glass substrates for perpendicular magnetic hard disks, but the reproduced output at short wavelengths was influenced by the surface roughness of the magnetic recording media. We therefore fabricated Co-Cr perpendicular hard disk media deposited onto different substrates: untextured glass, silicon single crystal, chemically textured alumite, and Mn-Zn ferrite. We compared these substrates with respect to their crystallographic properties, head-to-medium spacing, and record/playback characteristics.
Structures and magnetocrystalline anisotropy of single crystal permalloy films deposited by sputtering method.
Single crystal Permalloy films were grown epitaxially on (001) GaAs substrates by sputtering method. The relationship between crystal orientations for Permalloy and GaAs are (001)NiFe//(001) GaAs, NiFe// GaAs. The crystal structures of Permalloy films are deformed from cubic to tetragonal. The films of positive and negative tetragonal strain have small and large unit cell volume, respectively. The films with small lattice constant in the film plane have large strain distribution. The magnetocrystalline anisotropy for the films of large strain distribution is small, and that for films of negative tetragonal strain is large.
Effect of circumferential texture on the properties of thin film rigid recording disks
The magnetic recording medium of C/CoNiCr/Cr was DC magnetron sputtered onto rigid disk substrates of various circumferential textures. The texture was characterized by mechanical and optical surface profilometry. Texture increased circumferential coercivity and squareness. Recording signal and signal-to-noise ratio improved while overwrite worsened. Structural inhomogeneities in the carbon overcoat along the texture lines increased with texture. Texture improved the head-disk friction characteristics and increased the head lift-off time during start-up. Too coarse a texture led to performance degradation.