Patent ID: 7633714
Filing Date: 2009-12-15
Classification: G11B

Abstract:
1. A magnetic head for perpendicular magnetic recording comprising: a medium facing surface that faces toward a recording medium; a coil for generating a magnetic field corresponding to data to be written on the recording medium; a pole layer having an end face located in the medium facing surface, allowing a magnetic flux corresponding to the field generated by the coil to pass therethrough, and generating a write magnetic field for writing the data on the recording medium by means of a perpendicular magnetic recording system; and a shield, wherein: the shield incorporates: a first layer having a first surface located in a region of the medium facing surface forward of the end face of the pole layer along a direction of travel of the recording medium, a second surface closest to the pole layer, and a third surface opposite to the second surface; a second layer that is located on a side of the first layer farther from the pole layer, that has an end face located in the medium facing surface, and that touches the third surface of the first layer; a third layer disposed in a region sandwiching the pole layer with the first layer; a first coupling portion coupling the first layer to the third layer without touching the pole layer; and a second coupling portion located farther from the medium facing surface than the first coupling portion and coupling the pole layer to the third layer; the magnetic head further comprises a gap layer made of a nonmagnetic material and disposed between the pole layer and the first layer; in the medium facing surface, the first surface of the first layer is located at a specific distance created by a thickness of the gap layer from the end face of the pole layer; the end face of the pole layer has a side located adjacent to the gap layer, the side defining a track width; part of the coil passes through a space surrounded by the pole layer, the third layer, the first coupling portion and the second coupling portion; and in a cross section that intersects the end face of the pole layer and that is orthogonal to the medium facing surface and the third surface, a length of the second layer taken in a direction orthogonal to the medium facing surface is greater than a length of the first layer taken in the direction orthogonal to the medium facing surface.