MAGNETIC POWDER, ITS PRODUCTION METHOD, MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDING METHOD.

摘要

New magnetic powder has the compsn. MeO.n(FemGaxCryAlz03) where m is (2-x-y-z); Me is Ba, Sr, Pb, and/or Ca; n is 4.5-6; x,y and z are each at least 0; (x/3+y/4+z/6) is at least 1/6; (x/6+y/10+z/11) is not more than 1/6. At least 65% of the total number of particles in the powder falls within the range 0.5d - 1.5d, where d is the mean particle dia. Pref. the Fe content on the surface and in the interior of the particles is same. The powder is obtd. by pyrolysing the raw materials, spray-pulverising at high velosity and opt. surface-etching. The powder is combined with a binder to form the magnetic layer of a magnetic recording medium which can be used for thermal recording at 100-180 deg. C.