A. Ohtsubo

Design of a single-edge-sensitive thin film head core with perpendicular double layer medium

Achieving both high resolution and high read/write efficiency has been tried with a rather thick single-pole-head film core having the sensitive (ordinary) trailing edge and the less sensitive leading edge in the neighborhood of which a degradation of the magnetic flux density (Bs) is made. The degradation is made by laminating several sputtered layers of different alloy constitution of Co 1-x Zr x (x = 0.17-0.32). The whole film core consists of this degradation region of 4.2 μm thick and high permeability Co 0.85 Zr 0.03 Nb 0.12 region of 5.0 μm thick. Observed shallowing of the reproduce nulls in the wavelength response with the rather thick core shows a possible compatibility of the resolution and the efficiency.

Preparation of metal particulate smooth tape oriented longitudinally inside and perpendicularly at surface (MP-LIPS)

An LIPS tape and a relatively-random-inside-layer-PS (RIPS) tape with some perpendicular orientation and smoothness (Ra approximately 0.014 mu m, comparable to that of a longitudinal tape) were prepared with metallic iron needle particles by a novel method of magnetic orientation, which is described in detail. The LIPS and RIPS tapes showed higher output than a longitudinal tape at short wavelengths ( lambda >

A perpendicularly oriented coating of rice shaped iron particles

A new particulate recording medium containing iron fine particles of rice shape has been prepared, and its magnetic and surface properties are investigated. A special magnetic orientation technique was employed to orientate the particles of high saturation magnetization in order to reduce redisorientation of the particles due to demagnetization field and to minimize surface roughening effects occuring during the orientation process. Relatively high squareness ratio ( SQR\perp ) of the medium in the vertical direction was obtained such as SQR\perp= 0.65 after a correction for the demagnetization field, thus providing better recording characteristics especially in the short wave range.

Anisotropy of Microcrystalline Co-Nb-Zr-N Films

Field-induced anisotropy in Co-Nb-Zr-N soft magnetic thin films with 9 at% nitrogen was investigated. Samples were prepared by ion beam sputtering in Ar+N<inf>2</inf>. After pre-annealing for 1 hour at 600 °C, reversible relaxation of the field-induced anisotropy was observed, with ¿K<inf>ux</inf>=700 to 1500 J/m³. The dependences of the anisotropy on annealing temperature T<inf>ra</inf> and annealing time t<inf>ra</inf> were studied.

Measurement of Reflection Anisotropy of Polarized Light for Detecting Surface Perpendicular Orientation in MP-LIPS Tape

A rapid, non-destructive optical method for detecting the perpendicular orientation at the surface of metal LIPS tape is described. This technique uses reflection anisotropy due to the depolarization coefficient anisotropy of the acicular metal particles. A tape sample with low anisotropy according to this method of evaluation exhibited higher density wavelength response characteristics.

A Particulate Medium Oriented Longitudinally Inside and Perpendicularly at Surface

This report takes another look at the VAST (Vertical magnetic orientation-AC demagnetization-Smoothing period-sequential Train) technique used to fabricate double-layer particulate media oriented longitudinally inside and perpendicularly at the surface from CrO 2 particles and nitrocellulose with a urethane binder. Infrared irradiation was performed to evaporate the solvent instead of natural evaporation to improve the viscosity of the surface perpendicular oriented layer, and to ensure a controlled thin, uniform thickness surface layer.