| 摘要 |
PURPOSE:To obtain a magnetic powder which is composed of a substitution-type hexagonal-system ferrite having an appropriate coercive force and a high saturated magnetization degree and to obtain a magnetic recording medium whose magnetic flux density is large, whose electromagnetic conversion characteristic is excellent, whose surface electrical resistance is low and which is suitable for a perpendicular magnetic recording system by using the magnetic powder. CONSTITUTION:A magnetic layer which is composed mainly of a magnetic powder and a binder is formed on a non-magnetic support substance. The magnetic powder is composed of sheet-like particles whose alpha-Fe ratio obtained by the X-ray diffraction intensity is 2-20wt.% and whose remaining part is a hexagonal-system ferrite. A suitable material for this magnetic powder has a composition as expressed by a general formula on the right. The material composed of the sheet-like particles whose one part of Fe in the formula is in said alpha-Fe ratio can be enumerated. In the formula, A refers to at least one element selected from Ba, Sr, Pb and Ca; M<2+> refers to a bivalent ion of at least one element selected from Cu, Mn, Co, Zn, Ni and Ng; M<4+> refers to a guadrivalent ion of at least one element selected from Ti, Zr and Sn; n refers to a real number of 3-7; X refers to 0-0.2; y refers to 0-0.2; z refers to 0.03-0.26. |
