| 摘要 |
PURPOSE:To uniformalize the frequency characteristics in recording and reproduction by forming a continuous thin film of ferromagnetic iron oxide contg. Co on a disklike substrate while doping the thin film with Co so as to increase the coercive force of the resulting magnetic body toward the inside along the radial direction of the body. CONSTITUTION:A sintered Fe3O4 body as a target 4 is mounted on a disklike Al alloy substrate 1. The semicircular part of the circular target 4 on the substrate side is doped with 3% Co and the remaining half is not doped with Co to form a substrate 1 for a recording body composed of Fe3O42 doped with Co and undoped Fe3O43. While rotating the substrate 1 at 17r.p.m. as shown by the arrows, sputtering is carried out. By oxidizing the sputtered material at 290 deg.C in the air, a recording body 1 forming a continuous thin film of gamma-Fe2O3-base ferromagnetic iron oxide is obtd. The Co content of this circular target plate 10 is continuously reduced from the inside toward the outside to increase the coercive force toward the inside. Thus, a magnetic disk with uniformalized recording and reproducing characteristics is obtd. |
