Patent ID: 8493687
Filing Date: 2013-07-23
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 backward 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 forward 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 further includes a first coupling layer and a second coupling layer that magnetically couple the bottom shield and the yoke layer to each other; the first coupling layer is magnetically connected to the bottom shield, while the second coupling layer magnetically couples the first coupling layer to the yoke layer; 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 each of the first and second coupling layers is greater than the bottom shield and smaller than the yoke layer in length in the direction perpendicular to the medium facing surface; the first coupling layer has an end face that is located in the medium facing surface at a position backward of the end face of the bottom shield along the direction of travel of the recording medium; an end face of the second coupling layer closer to the medium facing surface is located at a distance from the medium facing surface; the second return path section magnetically couples the top shield and the main pole to each other; and 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.