PURPOSE: To obtain a magnetic record powder high in saturated magnetization by a method wherein at least a specific amount of one kind of Sr and Ba, Zn and Mg respectively and a specific amount of Cr, Ti, O respectively are included, and the remainder has a composition of Fe and comprises an oxide of a hexagonal W type ferrite crystal structure.
CONSTITUTION: In a magnetic record powder, at least one kind out of Sr and Ba is 1.0 to 3.0% and at least one kind out of Zn and Mg is 2.5 to 13.0%, and Cr is 9.0 to 18.0%, and Ti is 0.5 to 5.0%, and O is 57.0 to 61.0% by atom%, and the remainder has a composition composed of Fe and inevitable impurity and also comprises an oxide having a hexagonal W type ferrite crystal structure. Thus, a coercive force and a Curie point have the substantially same degree and saturated magnetization is increased as compared with a magnetic record powder of a hexagonal ferrite M type crystal structure, and when this powder is used in a magnetic card, a magnetic tape, a magnetic disk or the like, it is possible to reduce a use amount and thin a film of a record medium.
ISHIYAMA KOICHI
KOMADA KIICHI
