Magnetic recording head and magnetic recording/reproducing apparatus using the same

A magnetic recording/reproducing apparatus comprising:

• a magnetic recording medium;
• a magnetic recording head including:
• a magnetic pole having an air-bearing surface;
• a spin torque oscillator provided so that a first side of the spin torque oscillator faces the magnetic pole in a first direction parallel to the air-bearing surface;
• a first shield including a granular magnetic material provided so that the spin torque oscillator is sandwiched between two portions of the first shield in a second direction, the second direction being parallel to the air-bearing surface and perpendicular to the first direction;
• a second shield provided on a second side of the spin torque oscillator opposite to the first side;
• a first electrode;
• and
• a second electrode,
• wherein
• a resonant frequency of the granular magnetic material is higher than a frequency of a radio-frequency magnetic field generated by the spin torque oscillator;
• the spin torque oscillator includes a first magnetic layer having a coercivity lower than a magnetic field applied from the magnetic pole, a second magnetic layer having a coercivity lower than a magnetic field applied from the magnetic pole, and an intermediate layer provided between the first magnetic layer and the second magnetic layer;
• the first electrode is provided on a side of the first magnetic layer on which the intermediate layer is not provided, and capable of passing a current through the spin torque oscillator;
• and
• the second electrode is provided on a side of the second magnetic layer on which the intermediate layer is not provided, and capable of passing a current through the spin torque oscillator,
• a movable portion to enable a relative movement between the magnetic recording medium and the magnetic recording head so that the magnetic recording head flies above or in contact with the magnetic recording medium while facing the magnetic recording head;
• a position control unit to control the magnetic recording head so that the magnetic recording head is arranged on a predetermined recording position on the magnetic recording medium;
• and
• a signal processor to perform processing of a signal for writing on the magnetic recording medium and a signal for reading from the magnetic recording medium by the use of the magnetic recording head.