Seed layer and underlayer with high and low oxygen concentration portions for hand disk magnetic recording medium on a glass substrate
US6413608B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 18, 1999 |
| Grant date | Jul 2, 2002 |
| Priority date | — |
| Expiry date | Jun 18, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/265
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The thin film magnetic disk of the present invention includes a non-metallic substrate having a seed layer deposited on the substrate, an underlayer deposited upon the seed layer composed of a chromium alloy having a relatively high oxygen concentration portion of from 2,000 ppm to 20,000 ppm and preferably approximately 4,000 ppm to 12,000 ppm, followed by a relatively low oxygen concentration portion of from 0-2,000 ppm, and preferably from 500 ppm to 1,500 ppm and a magnetic layer that is deposited upon the underlayer. The underlayer total thickness is in the range of from approximately 250 å to approximately 700 å with a preferred thickness of approximately 450 å, wherein approximately half of the underlayer thickness is the high oxygen concentration portion and half is the low oxygen concentration portion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.