Longitudinal magnetic recording medium comprising a circumferentially textured disk substrate, chromium primer layer and a cobalt chromium magnetic alloy layer having a segregation structure

摘要

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 ANGSTROM 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 ANGSTROM , and the number of the surrounded low chromium concentration regions being from 600 to 1,500 regions/ mu m2.