| 摘要 |
PROBLEM TO BE SOLVED: To provide a storage medium assuring good short-wavelength output and S/N, small distortion of magnetization and small noise level by maintaining, to the value in the particular range, the variation coefficient of average grain size and grain size of the non-magnetic powder that is included in the non- magnetic layer on the carrier together with a binder. SOLUTION: An average grain size of non-magnetic powder is set to 20 to 200 m and variation coefficient of such gain size is controlled to 2 to 30%. As the non-magnetic powder,α-alumina havingα-conversion coefficient of 90% or more,β-alumina,γ-alumina, silicon carbide, chromium oxide, cerium oxide, hematite (α-iron oxide), goethite (oxy-iron dydroxide), corundum, silicon nitride, titanium carbide, titanium oxide, silicon dioxide, boron nitride, zinc oxide, calcium carbide, calcium sulfuric acid and barium sulfuric acid are used discretely or in combination. In regard to the magnetic storage medium, non-magnetic layer is provided on the carrier and the magnetic layer including a binder and a ferro-magnetic powder is provided thereon.
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