Abstract: According to one embodiment, a magnetic head includes a main pole configured to produce a recording magnetic field, a return pole opposed to a trailing side of the main pole across a write gap and configured to return magnetic flux from the main pole, a coil configured to excite the main pole, a spin-torque oscillator between the main pole and a surface of the return pole, configured to produce a high-frequency magnetic field, and side shields individually on opposite sides of the main pole transversely relative to a track, magnetically separated from the main pole, and located at a height position above the recording medium higher than that of the spin-torque oscillator.

Abstract: According to one embodiment, a magnetic head includes a main pole configured to produce a recording magnetic field, a return pole opposed to a trailing side of the main pole across a write gap and configured to return magnetic flux from the main pole, a coil configured to excite the main pole, a spin-torque oscillator between the main pole and a surface of the return pole, configured to produce a high-frequency magnetic field, and side shields individually on opposite sides of the main pole transversely relative to a track, magnetically separated from the main pole, and located at a height position above the recording medium higher than that of the spin-torque oscillator.

Abstract: According to one embodiment, a magnetic disk drive includes a magnetic disk to be subjected to perpendicular recording, a first pole core including a main pole configured to record signals on the magnetic disk, a first coil wound around the first pole core, a second pole core magnetically independent of the first pole core, tip ends of which are arranged on both sides of the main pole, a second coil wound around the second pole core, a read unit including an element configured to read data recorded on the magnetic disk, and a correction unit configured to correct a current phase difference between the first and second coils.