Patent ID: 9406318
Filing Date: 2016-08-02
CPC Classification: G11B,Y10T

Claim Text:
1. A magnetic head for perpendicular magnetic recording, 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 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 by means of a perpendicular magnetic recording system; a write shield formed of a magnetic material; a gap part formed of a nonmagnetic material and provided between the main pole and the write shield; a return path section; a nonmagnetic layer; and a substrate having a top surface, wherein the coil, the main pole, the write shield, the gap part, the return path section and the nonmagnetic layer are disposed above the top surface of the substrate, the write shield includes a bottom shield, a top shield, a first side shield and a second side shield, the first side shield and the second side shield being located on opposite sides of the main pole in a track width direction, the bottom shield has an end face that is located in the medium facing surface at a position on a rear side in a direction of travel of the recording medium relative to an end face of the main pole, the top shield has an end face that is located in the medium facing surface at a position on a front side in the direction of travel of the recording medium relative to the end face of the main pole, the first side shield has a first end face located in the medium facing surface, and has a first sidewall and a second sidewall facing the main pole, the second side shield has a second end face located in the medium facing surface, and has a third sidewall and a fourth sidewall facing the main pole, the first sidewall is connected to the first end face, the second sidewall is located farther from the medium facing surface than is the first sidewall, the third sidewall is connected to the second end face, the fourth sidewall is located farther from the medium facing surface than is the third sidewall, in any cross section intersecting the first and third sidewalls and parallel to the medium facing surface, a distance between the first sidewall and the third sidewall in the track width direction decreases with increasing proximity to the top surface of the substrate, each of the second and fourth sidewalls has an edge farthest from the top surface of the substrate, the edge of each of the second and fourth sidewalls is parallel to the medium facing surface and located at a distance of 20 to 120 nm from the medium facing surface, the main pole has the end face located in the medium facing surface, a top surface farthest from the top surface of the substrate, a bottom end opposite to the top surface of the main pole, and a first, a second, a third and a fourth side surface, the end face of the main pole has a first side located at an end of the top surface of the main pole, and has a second side and a third side opposite to each other in the track width direction, a distance between the second side and the third side in the track width direction decreases with increasing proximity to the top surface of the substrate, the first side surface is connected to the second side, the second side surface is located farther from the medium facing surface than is the first side surface, the third side surface is connected to the third side, the fourth side surface is located farther from the medium facing surface than is the third side surface, the first side surface is opposed to the first sidewall, a portion of the second side surface is opposed to the second sidewall, the third side surface is opposed to the third sidewall, a portion of the fourth side surface is opposed to the fourth sidewall, in any cross section intersecting the first and third side surfaces and parallel to the medium facing surface, a distance between the first side surface and the third side surface in the track width direction decreases with increasing proximity to the top surface of the substrate, the gap part includes a first portion interposed between the first sidewall and the first side surface and between the second sidewall and the second side surface, and a second portion interposed between the third sidewall and the third side surface and between the fourth sidewall and the fourth side surface, the main pole includes a main body, and a lower protrusion protruding from the main body toward the top surface of the substrate, the lower protrusion is located at a distance from the medium facing surface, the main body includes a front portion and a rear portion, the front portion being located closer to the medium facing surface than is the lower protrusion, the rear portion being located farther from the medium facing surface than is the front portion, the front portion includes the end face of the main pole and the first and third side surfaces of the main pole, the rear portion includes the second and fourth side surfaces, the lower protrusion has a bottom surface, a first side portion and a second side portion, the bottom surface facing toward the top surface of the substrate, the first and second side portions being opposite to each other in the track width direction, the return path section is formed of a magnetic material, located on the rear side in the direction of travel of the recording medium relative to the main pole, and connects the lower protrusion and the bottom shield to each other so that a space is defined by the main pole, the gap part, the bottom shield and the return path section, the return path section includes a connection layer in contact with the lower protrusion, the nonmagnetic layer is formed of a nonmagnetic material and disposed around the bottom shield and the connection layer, the bottom shield includes a first receiving section for receiving a portion of the lower protrusion, the nonmagnetic layer includes a second receiving section for receiving the remainder of the lower protrusion, the first receiving section has a bottom surface, a fifth sidewall and a sixth sidewall, the fifth sidewall being opposed to a portion of the first side portion, the sixth sidewall being opposed to a portion of the second side portion, the first sidewall has a first edge closest to the top surface of the substrate, the second sidewall has a second edge closest to the top surface of the substrate, the fifth sidewall has a third edge farthest from the top surface of the substrate, the sixth sidewall has a fourth edge farthest from the top surface of the substrate, the third edge is contiguous with the first edge, the fourth edge is contiguous with the second edge, and an entirety of the bottom surface of the lower protrusion is inclined with respect to a direction perpendicular to the medium facing surface such that the lower protrusion gradually increases in thickness with increasing proximity to the connection layer.