| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide hexagonal ferrite magnetic powder suitable for a high-density recording magnetic recording medium replayed by a sensitive head such as an MR head and GMR head, etc., in which noise is reduced without lowering σs, and a method for producing the powder, and the magnetic recording medium. <P>SOLUTION: The hexagonal ferrite magnetic powder having an average plate diameter of from 15 to 30 nm, Hc of from 2,000 to 5,000 Oe and σs of equal to or more than [the average plate diameter (nm)×0.37+45]Am<SP>2</SP>/kg. This magnetic powder is obtained by melting a substance containing a raw material in a region of a shaded area (1) in a triangular phase diagram shown in the figure, and quenching a molten product to obtain an amorphous product, subjecting the amorphous product to thermal treatment, acid treatment, and washing. Also, the magnetic recording medium is obtained by adding this magnetic powder to a magnetic layer and coating it on a support. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
