A current-assisted magnetic recording write head has an electrically conductive layer in the write gap between the write pole and the trailing shield. Electrical circuitry directs current between the write pole and the trailing shield, through the conductive layer in the write gap. The current through the conductive layer generates an Ampere field substantially orthogonal to the magnetization in the write pole to assist magnetization switching of the write pole. The conductive layer is wider in the cross-track direction than the trailing edge of the write pole and may extend beyond the write pole side gaps so as to be in contact with both the side shields and the trailing shield. The conductive layer may have substantially the same along-the-track thickness across its width or it may have a thicker central region at the write pole trailing edge and thinner side regions.

A current-assisted magnetic recording write head has an electrically conductive layer in the write gap between the write pole and the trailing shield. Electrical circuitry directs current between the write pole and the trailing shield, through the conductive layer in the write gap. The current through the conductive layer generates an Ampere field substantially orthogonal to the magnetization in the write pole to assist magnetization switching of the write pole. The conductive layer is wider in the cross-track direction than the trailing edge of the write pole and may extend beyond the write pole side gaps so as to be in contact with both the side shields and the trailing shield. The conductive layer may have substantially the same along-the-track thickness across its width or it may have a thicker central region at the write pole trailing edge and thinner side regions.

A current-assisted magnetic recording write head has an electrically conductive layer in the write gap between the write pole and the trailing shield. Electrical circuitry directs current between the write pole and the trailing shield, through the conductive layer in the write gap. The current through the conductive layer generates an Ampere field substantially orthogonal to the magnetization in the write pole to assist magnetization switching of the write pole. The conductive layer is wider in the cross-track direction than the trailing edge of the write pole and may extend beyond the write pole side gaps so as to be in contact with both the side shields and the trailing shield. The conductive layer may have substantially the same along-the-track thickness across its width or it may have a thicker central region at the write pole trailing edge and thinner side regions.

A heat-assisted magnetic recording head includes a write pole tip that extends to a media-facing surface and a heat sink that is thermally coupled to a side of the write pole tip. A surface plasmonic plate is in contact with a side of the heat sink that faces away from the write pole and is recessed from, the media-facing surface. A nanorod extends from a surface of the surface plasmonic plate and towards the media-facing surface.

According to one embodiment, in a magnetic disk, a plurality of first servo sectors is arranged at intervals in the circumferential direction. Each of the plurality of first servo sectors includes a first area and a second area. First information including a preamble, a servo mark, and a Gray code is written in the first area. The second area is disposed after the first area in a write and read direction along the circumferential direction, and second information including a burst pattern is written in the second area. The plurality of first servo sectors includes a plurality of second servo sectors and a plurality of third servo sectors. The circumferential length of a first area included in each of the plurality of third servo sectors is longer than the circumferential length of a first area included in each of the plurality of second servo sectors.

According to one embodiment, in a magnetic disk, a plurality of first servo sectors is arranged at intervals in the circumferential direction. Each of the plurality of first servo sectors includes a first area and a second area. First information including a preamble, a servo mark, and a Gray code is written in the first area. The second area is disposed after the first area in a write and read direction along the circumferential direction, and second information including a burst pattern is written in the second area. The plurality of first servo sectors includes a plurality of second servo sectors and a plurality of third servo sectors. The circumferential length of a first area included in each of the plurality of third servo sectors is longer than the circumferential length of a first area included in each of the plurality of second servo sectors.

A perpendicular magnetic recording (PMR) writer is configured to magnetically record data on a rotatable disk surface. The PMR writer including a pole tip, side shields, an air-bearing surface (ABS) region, a yoke region comprising Silicon Dioxide (SiO2), side gaps and a plurality of throat regions. The side gaps are arranged respectively between the pole tip and the side shields and include SiO2. A side gap width of the plurality of throat regions increases with a side shield throat height above the ABS region for each of the throat regions. The side gap width has a different width variation in each of the throat regions.