Magnetic recording medium

A thin film magnetic recording medium, having:

• at least 2 magnetic layers formed on a non-magnetic substrate;
• and
• a non-magnetic intermediate layer that is interposed between said magnetic layers and causes magnetizations of said magnetic layers to be anti-parallel to one another;
• wherein a ratio HkB/HkA of an anisotropic magnetic field strength HkB of a magnetic layer on a side near to said substrate to an anisotropic magnetic field strength HkA of a magnetic layer on a side far from said substrate is 0.7 or less, and
• wherein a ratio HcoB/HcoA of a coercivity HcoB of the magnetic layer B on the side near to said substrate at 0K as obtained by extrapolating values of coercivity at 200K and 100K to a coercivity HcoA of the magnetic layer A on the side far from said substrate at 0K as obtained by extrapolating values of coercivity at 200K and 100K is 0.7 or less.

A thin film magnetic recording medium, having:

• at least 2 magnetic layers formed on a non-magnetic substrate;
• and a non-magnetic intermediate layer that is interposed between said magnetic layers and causes magnetizations of said magnetic layers to be anti-parallel to one another;
• wherein a ratio HkB/HkA of an anisotropic magnetic field strength HkB of a magnetic layer on a side near to said substrate to an anisotropic magnetic field strength HkA of a magnetic layer on a side far from said substrate is 0.7 or less, and
• wherein a value (HcoA−HcoB)/(πa*dH/dx) is 0.8 or more, where HcoB is a coercivity of the magnetic layer B on the side near to said substrate at 0K as obtained by extrapolating values thereof at 200K and 100K, HcoA is a coercivity of the magnetic layer A on the side far from said substrate at 0K as obtained by extrapolating values thereof at 200K and 100K, dH/dx is a derivative in a track direction of a track direction component of a magnetic field from a magnetic recording head used together with said magnetic recording medium in a magnetic recording/playback device, taken in a position where said track direction component is HcoA in the center of the track and the center of the thickness direction of said magnetic layer A, and πa is a magnetic transition width of an isolated transition formed on said magnetic recording medium using said magnetic recording head.

A thin film magnetic recording medium, having:

• at least 2 magnetic layers formed on a non-magnetic substrate;
• and
• a non-magnetic intermediate layer that is interposed between said magnetic layers and causes magnetizations of said magnetic layers to be anti-parallel to one another;
• wherein a ratio HkB/HkA of an anisotropic magnetic field strength HkB of a magnetic layer on a side near to said substrate to an anisotropic magnetic field strength HkA of a magnetic layer on a side far from said substrate is 0.7 or less, and
• wherein during a process in which, at a temperature of 30K, a magnetic field is applied in a track direction to cause magnetic saturation, then the magnetic field is reduced at a rate of 3,000A/m per second, and then a magnetic field is applied in an opposite direction to cause magnetic saturation, the derivative of magnetization with respect to magnetic field strength has at least 2 peaks, and the magnetic field strengths giving said peaks are all in said direction of the last magnetic saturation.

A thin film magnetic recording medium, having:

• at least 2 magnetic layers formed on a non-magnetic substrate;
• and
• a non-magnetic intermediate layer that is interposed between said magnetic layers and causes magnetizations of said magnetic layers to be anti-parallel to one another;
• wherein a ratio HkB/HkA of an anisotropic magnetic field strength HkB of a magnetic layer on a side near to said substrate to an anisotropic magnetic field strength HkA of a magnetic layer on a side far from said substrate is 0.7 or less, and
• wherein said magnetic recording medium comprises at least 2 magnetic layers formed on a non-magnetic substrate;
• and a non-magnetic intermediate layer that is interposed between said magnetic layers and causes magnetizations of said magnetic layers to be anti-parallel to one another, and wherein a saturation magnetization of said magnetic layer on a side near to said substrate is larger than a saturation magnetization of said magnetic layer on a side far from said substrate.