| 摘要 |
PURPOSE:To increase the recording density and data transmission speed by making the coercive force of a magnetic film at the inner circumference of a disk larger than that at the outer circumference so as to improve the frequency characteristics as a whole by improvement in the frequency characteristics at the inner circumference. CONSTITUTION:The diagram shows the coercive force Hc of a magnetic film corresponding to the distance from the center of a disk. The magnetic film has larger Hc at the inner circumference (a) of the disk than at the outer circumference (b), and the Hc is gradually increased from the outer circumference (b) toward the inner circumference (a). In order to change the Hc value, for example, the amount of Co contained in a gamma-Fe2O3 film at the inner circumference (a) of the disk is regulated to 2.5wt%, and the amount of Co contained in the film at the outer circumference (b) to 1.0wt%. Since the extent of flotation of a magnetic head is reduced at the inner circumference (a), saturation writing can be carried out well in spite of the large Hc. |
