Method of increasing the coercivity of magnetite films
US3996395A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 26, 1972 |
| Grant date | Dec 7, 1976 |
| Priority date | — |
| Expiry date | May 26, 1992 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/70694
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of increasing the coercivity of a magnetic device having a magnetite film reduced from alpha ferric oxide. The alpha ferric oxide film is reduced to magnetite by subjecting it to a temperature greater than 400.degree. C in a reducing atmosphere. The temperature of the film is then changed to between about 150.degree. and 300.degree. C, and the reducing atmosphere is replaced by an oxidizing atmosphere. The film is subjected to the oxidizing atmosphere while the temperature is held between 150.degree. and 300.degree. C, thus causing the magnetite film to become partially oxidized to form a solid solution of magnetite and gamma ferric oxide as represented by the formula, (1-x)Fe.sub.3 O.sub.4 .sup.. xFe.sub.2 O.sub.3, where x is between 0.49 and 0.85.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.