| 摘要 |
PURPOSE:To satisfy vertical magnetic anisotropy and coercivity, which are required as a vertical magnetic recording medium that comprises calcium oxide, cobalt oxide and iron oxide, by limiting each component at specified composition ratios. CONSTITUTION:A material comprises calcium oxide, cobalt oxide and iron oxide. The material is expressed by a general formula: CaO-yCoO-zFeO3/2 (where x, y and z represent mol percentages of their components, and x+y+z=100). Then the composition ratios lie in a range surrounded by a polygon A1A3E3E1, in which x, y and z correspond to apexe points A1, A3 E3 and E1 in the Table that are the apexes of the polygon (except for the composition ratios on the lines connecting the points A1, A3, E3 and E1). Thus the magnetic recording material, which is chemically stable and satisfied the characteristic required for vertical magnetic recording and optical magnetic recording, is obtained.
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