Perpendicular magnetic recording media of amorphous (Fe4Co6)80B20ultrafine particle films

Amorphous (Fe4Co6)80B20ultrafine particles(UFP) formed on a substrate by sputtering exhibit high coercive force and large perpendicular magnetic anisotropy. The material having those magnetic properties basically can be applied to perpendicular recording media. A double layer coating of polymer and AlN on the ultrafine particles resulted in good mechanical properties of the media such as upright standing of each particle and durability of the coating. There were almost no changes in magnetic properties between before and after coating the UFP. Magnetic recording characteristics of the UFP film were evaluated and it was found that the UFP film was perpendicularly recorded. Subsequent annealing of the UFP film at around 450°C brought on considerable improvement of the magnetic properties, increasing magnetization, coercive force and magnetic anisotropy. Dipulse ratio obtained was about 0.45 for coating thickness of 0.2 μm.