Magnetic medium for longitudinal recording

A magnetic recording medium comprising

• a first magnetic layer configured to record information in a longitudinal direction therein,
• a second magnetic layer disposed adjacent to said first magnetic layer, said second magnetic layer being magnetically soft relative to said first magnetic layer and constructed to remain unsaturated during reading of said information from said first magnetic layer, and
• a nonmagnetic layer disposed between said first magnetic layer and said second magnetic layer,
• wherein each one of said magnetic layers has a magnetic thickness equal to a product of a geometric thickness thereof and a remanence thereof, the magnetic thickness of said second magnetic layer being greater than the magnetic thickness of said first magnetic layer.

Magnetic medium for longitudinal recording in a system in which a head passes over the medium at an effective fly height during operation, said magnetic medium comprising:

• a first magnetic layer disposed adjacent to the head and configured to record information in a longitudinal direction therein;
• a nonmagnetic layer disposed beneath said first magnetic layer;
• and
• a second magnetic layer disposed beneath said nonmagnetic layer and being magnetically soft relative to said first magnetic layer.

A magnetic medium for longitudinal recording in a system in which a head passes over the medium at an effective fly height during operation, said magnetic medium comprising:

• a first magnetic layer disposed adjacent to the head and configured to record information in a longitudinal direction therein,
• a nonmagnetic layer disposed beneath said first magnetic layer, and
• a second magnetic layer disposed beneath said nonmagnetic layer and being magnetically soft relative to said first magnetic layer,
• wherein each one of said magnetic layers has a magnetic thickness equal to a product of a geometric thickness thereof and a remanence thereof, the magnetic thickness of said second magnetic layer being greater than that of said first magnetic layer.

Recording system comprising:

• a head adapted to pass over said medium at an effective fly height during operation;
• a magnetic recording medium comprising
• a first magnetic layer disposed adjacent to the head and configured to record information in a longitudinal direction therein;
• a nonmagnetic layer disposed beneath said first magnetic layer;
• and
• a second magnetic layer disposed beneath said nonmagnetic layer and being magnetically soft relative to said first magnetic layer.

A magnetic recording medium comprising

• a first magnetic layer configured to record information in a longitudinal direction therein,
• a second magnetic layer disposed adjacent to said first magnetic layer, said second magnetic layer being magnetically soft relative to said first magnetic layer and constructed to remain unsaturated during reading of said information from said first magnetic layer, and
• a nonmagnetic layer disposed between said first magnetic layer and said second magnetic layer,
• wherein the second magnetic layer has a uniaxial anisotropy, said medium is configured as a disk, and the uniaxial anisotropy is in a radial direction.

A magnetic recording medium comprising

• a first magnetic layer configured to record information in a longitudinal direction therein,
• a second magnetic layer disposed adjacent to said first magnetic layer, said second magnetic layer being magnetically soft relative to said first magnetic layer and constructed to remain unsaturated during reading of said information from said first magnetic layer, and
• a nonmagnetic layer disposed between said first magnetic layer and said second magnetic layer,
• wherein said first magnetic layer has a geometric thickness (t.sub.m) and a magnetic remanence (M.sub.R) and said second magnetic layer is semi-hard having a coercivity H.sub.c according to the relationship:
• (t.sub.m M.sub.R /2.pi.d)>H.sub.c >(t.sub.m M.sub.R /2.pi.)((1/(2h+d))-(1/(2h+3d)))
• wherein (h) is the effective flying height of a recording head over said medium and (d) is the geometric thickness of said nonmagnetic layer.

A recording system comprising

• a magnetic recording medium, and
• a head for writing information to and reading information from said medium, said head being disposed to pass over said medium at an effective fly height during operation,
• said magnetic recording medium including
• a first magnetic layer disposed adjacent to the head and configured to record information in a longitudinal direction therein, and
• a second magnetic layer disposed beneath said first magnetic layer, said second magnetic layer being magnetically soft relative to said first magnetic layer and constructed so that all portions of said second layer disposed adjacent to a portion of said information recorded in said first layer remain unsaturated during reading of said portion of said information by said head.