| 摘要 |
PURPOSE:To prevent the deterioration of characteristics caused by change of environmental temperature, and obtain magnetic powder of optimum particle and recoding medium of high S/N, by substituting a part of Fe atoms in specified hexagonal system ferrite magnetic powder by specified metal and Sn atoms in a specified range. CONSTITUTION:A part of Fe atoms as the constituting element of hexagonal system ferrite magnetic powder, wherein the average grain diameter is 0.02-0.2mum and coerecive force is 200-2000Oe, is substituted by the following and magnetic powder is constituted; bivalent metal, at least one kind of metal selected out of tetravalent metal and hexavalent metal, and Sn atoms in the range larger than 0.5 and smaller than or equal to 1.0per chemical formula. Recording medium is constituted by making hexagonal system ferrite magnetic powder attach on the surface of a retainer or by spreading said powder together with binder resin on said surface. By this constitution, the deterioration of output, regeneration, erasing characteristics, and over-writing characteristics due to variation in ambient temperature can be prevented, and noise at the time of regeneration is reduced in the case of recording medium use. Thereby recording medium of high S/N ratio can be obtained. |
