Multi-layer amorphous magneto optical recording medium
US4569881A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 12, 1984 |
| Grant date | Feb 11, 1986 |
| Priority date | — |
| Expiry date | Apr 12, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2495
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A multi-layer magneto optical thin film recording medium is disclosed having very high carrier-to-noise ratios (at least 47 decibels) and high rotation angles. A transmission electron microscope photomicrograph (at 200,000 X) of one such medium is shown in FIG. 1. The magneto optic layer is a multi-phase amorphous material having magnetic anisotropy perpendicular to the plane of the thin film produced in a triode vacuum sputtering process at vacuums in the range of 4.times.10.sup.-3 to 6.times.10.sup.-4 Torr. Various transparent layers, such as dielectric intermediate and anti-reflective layers and a protective covering layer, are combined with the magneto optic layer and a reflective surface to yield media having enhanced carrier-to-noise ratio and magnetic optic angle of rotation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.