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AssigneeMitsubishi Kasei Corporation
InventorsYukihiro Miyamoto, Fumiaki Yokoyama
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A longitudinal magnetic recording medium comprising a non-magnetic substrate having a texture with a arithmetric average roughness Ra in a circumferential direction of at least 20 .ANG. and a magnetic alloy layer comprising cobalt and chromium as the main components, formed on the substrate, wherein the magnetic alloy layer has (i) a feature that when the orientation degree of the hcp crystal structure is represented by the diffraction ray intensity of electron diffraction by transmission electron diffractiometry, the intensity ratio of the electron diffraction ring in the Co (002) plane between the circumferential direction and the radial direction of the substrate is at least 3, and (ii) a segregation structure having low chromium concentration regions surrounded by high chromium concentration regions, the diameters of the defined low chromium concentration regions being within a range of from 80 to 500 .ANG., and the number of the surrounded low chromium concentration regions being from 600 to 1,500 regions/.mu.m.sup.2.
A longitudinal magnetic recording medium comprising a non-magnetic substrate in the form of a disk having a texture provided in a circumferential direction of the medium, with an arithmetric average roughness Ra measured in a radial direction of at least 20 angstroms, a non-magnetic chromium primer layer and a magnetic alloy layer comprising cobalt and chromium as the main components, formed on the substrate, wherein the magnetic alloy layer has (i) a feature that when an orientation degree of a hcp crystal structure is represented by diffraction ray intensity of electron diffraction by transmission electron diffractiometry, the intensity ratio of the electron diffraction ring in a Co (002) plane between the circumferential direction and the radial direction of the substrate is at least 3, and (ii) a segregation structure having cobalt chromium regions with a lower chromium concentration and a higher intensity of magnetization than surrounding cobalt chromium regions, diameters of the surrounded cobalt chromium regions being within a range of from 80 to 500 angstroms, and a number of the surrounded cobalt chromium regions being from 600 to 1,500 regions/.mu.m.sup.2.
A longitudinal magnetic recording medium comprising a non-magnetic substrate in the form of a disk having a texture provided in a circumferential direction of the medium with an arithmetric average roughness Ra measured in a radial direction of at least 20 .ANG. provided on an aluminum alloy plate having a Ni-P layer formed by electroless plating, and a magnetic alloy layer comprising cobalt and chromium as the main components, formed on the substrate with a non-magnetic chromium primer layer having a thickness of from 500 to 2,000 .ANG. interposed therebetween, wherein the magnetic alloy layer has (i) a feature that when an orientation degree of a hcp crystal structure is represented by diffraction ray intensity of electron diffraction by transmission electron diffractiometry, the intensity ratio of the electron diffraction ring in a Co (002) plane between the circumferential direction and the radial direction of the substrate is at least 3, and (ii) a segregation structure having cobalt chromium regions with a lower chromium concentration and a higher intensity of magnetization than surrounding cobalt chromium regions, diameters of the surrounded cobalt chromium regions being within a range of from 80 to 500 .ANG., and a number of the surrounded cobalt chromium regions being from 600 to 1,500 regions/.mu.m.sup.2, and a protecting layer is formed on the magnetic alloy layer, and a lubricating layer is formed further thereon.
Dependencies are inferred from the claim text.