Patent ID: 8749919
Filing Date: 2014-06-10
Classification: G11B

Abstract:
1. A magnetic head for perpendicular magnetic recording, comprising: a medium facing surface that faces a recording medium; a coil that produces a magnetic field corresponding to data to be written on the recording medium; a main pole that has an end face located in the medium facing surface, allows a magnetic flux corresponding to the magnetic field produced by the coil to pass, and produces a write magnetic field for writing the data on the recording medium by means of a perpendicular magnetic recording system; a shield made of a magnetic material and having an end face that is located in the medium facing surface to wrap around the end face of the main pole; a gap part made of a nonmagnetic material and provided between the main pole and the shield; a first return path section and a second return path section each made of a magnetic material; and a substrate on which the coil, the main pole, the shield, the gap part, the first return path section, and the second return path section are stacked, the substrate having a top surface, wherein: the shield includes a bottom shield, first and second side shields, and a top shield; the bottom shield has an end face that is located in the medium facing surface at a position on a leading side of the end face of the main pole along a direction of travel of the recording medium; the first and second side shields have two end faces that are located in the medium facing surface at positions on opposite sides of the end face of the main pole in a track width direction; the top shield has an end face that is located in the medium facing surface at a position on a trailing side of the end face of the main pole along the direction of travel of the recording medium; the first return path section includes a yoke layer, and a coupling layer that magnetically couples the bottom shield and the yoke layer to each other; in a cross section that intersects the end face of the main pole located in the medium facing surface and that is perpendicular to the medium facing surface and the top surface of the substrate, the yoke layer is greater than the bottom shield in length in a direction perpendicular to the medium facing surface, and the coupling layer is greater than the bottom shield and smaller than the yoke layer in length in the direction perpendicular to the medium facing surface; the second return path section magnetically couples the top shield and the main pole to each other; the coil includes a first portion that passes through a space defined by the main pole and the first return path section, and a second portion that passes through a space defined by the main pole and the second return path section; the main pole has a bottom end which is an end closer to the top surface of the substrate, and has a top surface opposite to the bottom end; the bottom end of the main pole includes a first portion and a second portion that are contiguously arranged in order of increasing distance from the medium facing surface; a distance from the top surface of the substrate to any given point on each of the first and second portions of the bottom end of the main pole decreases with increasing distance from the given point to the medium facing surface; the bottom shield has a top surface that is opposed to the first portion of the bottom end of the main pole with the gap part interposed therebetween; a distance from the top surface of the substrate to any given point on the top surface of the bottom shield decreases with increasing distance from the given point to the medium facing, surface; and in the cross section, the second portion of the bottom end of the main pole is located farther from the medium facing surface than is the top surface of the bottom shield.