Platelike magnetic powder and a recording medium which uses the platelike magnetic powder
US4886714A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 9, 1988 |
| Grant date | Dec 12, 1989 |
| Priority date | — |
| Expiry date | May 9, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/70678
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention provides a platelike magnetic powder made from a magnetic powder having particles each of which has a portion comprising the spinel type crystal structure and a portion comprising the magnetoplumbite type crystal structure. The magnetic powder provides a large saturation magnetization .sigma.s and a small temperature change .DELTA.Hc/.DELTA.T of coercive force in the vicinity of the room temperature. Further, the present invention is to provide a high density magnetic recording medium which uses the magnetic powder. Furthermore, the present invention is to provide, a method to easily manufacture the magnetic powder by the coprecipitation method. A raw material powder of superfine particles is prepared. The prepared powder is fired at a low temperature in a non-oxidizing atmosphere.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.