| 摘要 |
A magnetic recording medium, comprising: a substrate; an underlayer formed on the substrate; and a spinel-type iron oxide thin film comprising maghemite as a main component formed on the underlayer, the spinel-type iron oxide thin film having a thickness (t) of 5 to 50 nm, being constituted by grains having an average grain size (D) of 5 to 30 nm, a standard deviation of grain sizes of not more than 4 nm and a ratio (D/t) of the average grain size (D) to the thickness (t) of less than 1.0, and exhibiting a coercive force of not less than 159 kA/m (2,000 Oe) and a coercive squareness ratio S* of not less than 0.5:1 in a longitudinal recording medium or a squareness ratio not less than 0.75:1 in a perpendicular recording medium. The magnetic recording medium exhibits a high coercive force and an excellent squareness.
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