| 摘要 |
PURPOSE:To obtain a magnetic disk having high thermal stability and suitable for high density recording by incorporating teraxially anisotropic magnetic iron oxide powder contg. cobalt and having a sharp major axis size distribution in which the half-width of the distribution curve divided by a major axis size corresponding to the maximum value of the distribution curve gives <=0.5 into a magnetic layer. CONSTITUTION:Magnetic iron oxide powder contg. cobalt is teraxially anisotropic needlelike magnetic powder contg. cobalt solubilized in magnetic iron oxide powder and having a sharp major axis size distribution in which the half- width of the distribution curve divided by a major axis size corresponding to the maximum value of the distribution curve gives <=0.5. The needlelike magnetic powder has a component with high residual magnetization in any direction, and the direction of easy manetization is isotropic, so when the powder is used in the manufacture of a magnetic disk which is subjected to magnetic recording in the circumferential direction, favorable magnetic recording is carried out, high output is obtd., and the recording density is increased. |
