Perpendicular magnetic recording medium and process for production of the same

A process of production of a perpendicular magnetic recording medium which forms a magnetic layer having a main surface and being made by a vapor deposition method on a nonmagnetic support, characterized in that there is an angle .THETA. between a normal direction of the main surface of the nonmagnetic support and a direction of incidence of a flow of vapor from a source of vaporization at the time of forming the magnetic layer such that the angle .THETA. is within a range of 10.degree. to 40.degree. such that a half-value width of a switching field distribution obtained from a remanent magnetization curve in a direction of an axis of easy magnetization of the magnetic layer from which a shape magnetic anisotropy has been removed is no more than 40 kA/m.

A method of perpendicular magnetic recording and/or reproduction characterized in that recording is performed using ring magnetic heads with a gap length Lg of no more than 0.18 .mu.m on a perpendicular magnetic recording medium having as a magnetic layer on a nonmagnetic support a metal magnetic thin film which has a half-value width of a switching field distribution obtained from a remanent magnetization curve in an easy direction of magnetization from which a shape magnetic anisotropy is removed of no more than 40 kA/m.

A method of perpendicular magnetic recording and/or reproduction characterized in that recording is performed using ring magnetic heads with a gap length Lg of no more than 0.18 .mu.m on a perpendicular magnetic recording medium having a magnetic layer on a nonmagnetic support, the magnetic layer having a main surface and comprising a metal magnetic thin film which has an angle .THETA..sub.E formed between axes of easy magnetization of the magnetic layer from which a shape magnetic anisotropy is removed and a normal direction of the main surface of the magnetic layer of 10.degree..ltoreq..theta..sub.E .ltoreq.40.degree. and in which a half-value width of a switching field distribution obtained from a remanent magnetization curve in a direction of an axis of easy magnetization of the magnetic layer from which a shape magnetic anisotropy has been removed is no more than 40 kA/m.

A method of perpendicular magnetic recording and/or reproduction characterized in that recording is performed using ring magnetic heads with a gap length Lg of no more than 0.18 .mu.m on a perpendicular magnetic recording medium having a magnetic layer by recording digital signals while causing the ring magnetic heads to run along a direction which is tilted with respect to an axis of easy magnetization of the magnetic layer, the magnetic layer being provided as a metal magnetic thin film on a non-magnetic support, the metal magnetic thin film having a half-value width of a switching field distribution obtained from a remanent magnetization curve in an easy direction of magnetization from which a shape magnetic anisotropy is removed of no more than 40 kA/m.