Magnetic material, magnetic recording medium, and method of manufacturing a magnetic material
US4904530A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 4, 1987 |
| Grant date | Feb 27, 1990 |
| Priority date | — |
| Expiry date | May 4, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2982
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention relates to a magnetic material for use in the magnetic recording and playback of information, which material consists of ferrite particles having the composition A.sub.1-y Zn.sub.y Fe.sub.2 O.sub.4, wherein A is one or more bivalent metal ions, which material is suitable for use in a recording medium having a high information density in that the magnetic material comprises monodisperse ferrite particles having an average particle size between 5 and 250 nm, preferably between 10 and 50 nm, and in that y is between 0.05 and 0.35. The magnetic material preferably is Co-Zn-ferrite. The material is manufactured by coprecipitation of a mixture of hydroxides succeeded by recrystallization at elevated temperature and pressure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.