Three-dimensional magnetic recording and reproducing apparatus including a plurality of magnetic layers having different resonant frequencies

A three-dimensional magnetic recording and reproducing apparatus, comprising:

• a recording head comprising a first spin-torque oscillator comprising a first free layer, a first non-magnetic layer and a first fixed layer, magnetization of the first free layer being rotatable, the first non-magnetic layer being laminated on the first free layer, the first fixed layer being laminated on the first non-magnetic layer, a magnetization direction of the first fixed layer being fixed;
• a reading head comprising a second spin-torque oscillator comprising a second free layer, a second non-magnetic layer and a second fixed layer, magnetization of the second free layer being rotatable, the second non-magnetic layer being laminated on the second free layer, the second fixed layer being laminated on the second non-magnetic layer, a magnetization direction of the second fixed layer being fixed;
• and
• a magnetic storage medium comprising a plurality of first magnetic layers formed of magnetic materials having different resonant frequencies, each of the first magnetic layers being formed of an in-plane magnetization film and having recording tracks, a magnetization direction in the in-plane magnetization film being oriented parallel to the film plane and vertical to the recording tracks in order to reduce dipole interaction between bits of adjacent layers and between adjacent bits in the same layer.