Osamu Morita

Characterization of magnetizing process for pre-embossed servo pattern of plastic hard disks

Rigid disks which have pre-embossed servo patterns have been developed. These media make it possible to follow tracks less than 5 /spl mu/m pitch. The substrates are made from plastic; and pre-embossed servo patterns and discrete data tracks are made by a stamping technology similar to optical disks. To generate signals from pre-embossed servo patterns, the magnetization direction of the elevated pattern and recessed area must be opposing. Therefore, a two-step magnetization method has been developed. Based on experimental results, optimum conditions are met when the magnetization transition occurs at the upper edge of the patterns. >

The thin film head for VCR

We have investigated a thin film head for VCR application whose structure has a long depth and a gap surface that is perpendicular to the substrate. We made a test device that has a CoZr amorphous thin film core. The conductor is a helicoid that is wound three-dimensionally around the core and is fabricated by thin film processes. The thin film head obtained larger normalized output voltage by track width and inductance than a MIG head between 1 to 10 MHz. >

The durability of new rigid disks by molded plastic substrates (abstract)

Media that have discrete data tracks and servo pits for rigid disk systems have been developed.1 Discrete data tracks and servo pits are embossed on plastic substrates by a stamping technique similar to that used in optical disk technology. The outer diameter of the substrates is 65 mm, and the thickness is 1.2 mm. To enhance the durability of contact‐start‐stop (CSS) environment and reduce glide height, we have developed a method of texturing the surface with a fine dispersion of SiO2 particles, whose diameters are between 10 and 40 nm, by dipping. Thin film layers are then sputtered on the substrates, and the shapes of SiO2 particles are reflected in the surface profile of the thin film layers. The initial friction coefficient (μi) is 0.46, and the friction coefficient after 50u2009000 CSS events is 0.56 for CSS tests on molded plastic substrates at a radius of 28 mm. In addition, glide height depends on surface roughness of the disks. Surface roughness of a glass template used on stampers is carried over t...