Patent ID: 9218827
Filing Date: 2015-12-22
Classification: G11B

Abstract:
1. A thermally-assisted magnetic recording head comprising: a medium facing surface configured to face a recording medium; a coil configured to produce a magnetic field corresponding to data to be written on the recording medium; a main pole having a first end face located in the medium facing surface, the main pole being configured to allow a magnetic flux corresponding to the magnetic field produced by the coil to pass, and configured to produce a write magnetic field for writing the data on the recording medium; a return path section formed of a magnetic material and having a second end face located in the medium facing surface, the return path section being connected to the main pole and configured to allow a magnetic flux corresponding to the magnetic field produced by the coil to pass; a waveguide including: a core which has a front end face facing toward the medium facing surface and is configured to allow light to propagate therethrough; and a cladding provided around the core; and a plasmon generator including a near-field light generating part located in the medium facing surface, wherein the second end face is located on a rear side in a direction of travel of the recording medium relative to the first end face, the near-field light generating part is located between the first end face and the second end face, the main pole is located on a front side in the direction of travel of the recording medium relative to the core, the plasmon generator is configured so that a surface plasmon is excited on the plasmon generator based on the light propagating through the core, and the near-field light generating part generates near-field light based on the surface plasmon, the main pole further has a top surface which is a surface lying at a front-side end of the main pole in the direction of travel of the recording medium, the return path section includes a first yoke portion located on the front side in the direction of travel of the recording medium relative to the main pole and in contact with the top surface of the main pole, the coil includes a plurality of coil elements extending to pass between the core and the first yoke portion, the plurality of coil elements include a specific coil element, in a cross section that intersects the first end face of the main pole and is perpendicular to the medium facing surface and parallel to the direction of travel of the recording medium, the specific coil element has a bottom end portion lying at a rear-side end of the specific coil element in the direction of travel of the recording medium, a top end portion lying at a front-side end of the specific coil element in the direction of travel of the recording medium, a front end portion closest to the medium facing surface, and a rear end portion farthest from the medium facing surface, and the main pole includes: a first portion lying between a first imaginary plane and a second imaginary plane which are perpendicular to the direction of travel of the recording medium, the first portion being closer to the medium facing surface than is the specific coil element; and a second portion lying between a third imaginary plane and a fourth imaginary plane which are parallel to the medium facing surface, the second portion being located on the front side in the direction of travel of the recording medium relative to the specific coil element, the first imaginary plane passing through the bottom end portion of the specific coil element, the second imaginary plane passing through the top end portion of the specific coil element, the third imaginary plane passing through the front end portion of the specific coil element, the fourth imaginary plane passing through the rear end portion of the specific coil element.