Correlation of composition and angular uniformity with performance in magneto-optic disks prepared from alloy targets

Journal Article · Tue May 01 00:00:00 EDT 1990 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.344592· OSTI ID:7123618

Hatwar, T K; Genova, D; Stinson, D G ^[1]

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1. Optical Recordings Materials Laboratory, Diversified Technologies Group, Eastman Kodak Company, Rochester, New York 14560-2017 (USA)

Sputtering from an alloy target is the preferred method for the production of magneto-optic recording media. However, when sputtering from an alloy target, the angular dependence of the deposition rate of the rare-earth elements is different from that of the transition-metal elements, causing film composition to vary with position. TbFeCo-based media were deposited on 130-mm-diam glass disks from 2-in.-diam alloy targets, under varying composition and sputtering conditions. Coercivity, Kerr rotation, and reflectivity were measured as a function of position on the disk. Dynamic performance as a function of record power was determined for 1.0-MHz recording at 7 m/s linear velocity (3.5-{mu}m marks). It was found that the angular (in-track) uniformity of the magnetic properties, as well as the average composition and magnetic properties, is correlated to noise level. Systematic variations in the noise level and the carrier-to-noise ratio (CNR) were observed as a function of the film composition. Minimum noise and thus the highest CNR (greater than 60 dB in a 30-kHz-resolution bandwidth) was obtained at a film composition near the compensation point.

• OSTI ID: 7123618
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 67:9; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ALLOYS
AMORPHOUS STATE
COBALT ALLOYS
COERCIVE FORCE
DIELECTRIC PROPERTIES
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
IRON ALLOYS
KERR EFFECT
LASER RADIATION
MAGNETIC DISKS
MAGNETIC PROPERTIES
MAGNETIC STORAGE DEVICES
MAGNETO-OPTICAL EFFECTS
MEMORY DEVICES
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
RARE EARTH ALLOYS
REFLECTIVITY
SPUTTERING
SURFACE PROPERTIES
TERBIUM ALLOYS