Ferromagnetic ultrafine particles, method of making, and recording medium using the same

摘要

Ultrafine particles of Fe-Co-P material with a Fe/Co atomic ratio of from 95/5 to 70/30 and a (Fe+Co)/P atomic ratio of from 85/15 to 60/40 show improved ferromagnetic properties. The average particle size is from 0.005 to 0.1 mu m. Such ultrafine particles are prepared through gas phase reaction by evaporating a source material. They are useful in both magnetic and thermomagnetic recording media ensuring high density recording.