Abstract: According to one embodiment, a magnetic disk device includes a disk, a head which writes data to the disk and reads data from the disk, and a controller which increases a first recording density of data to be written to a first sector having a first overwrite in the first sector and reduces a second recording density of data to be written to a second sector having a second overwrite different from the first overwrite, on a first track of the disk.

Abstract: According to one embodiment, a magnetic recording and reproducing device includes a magnetic flux control layer provided between a main magnetic pole and an auxiliary magnetic pole, and a protective layer provided on an ABS of the auxiliary magnetic pole. The magnetic flux control layer includes an adjustment layer formed of a magnetic material including one of Fe, Co or Ni and is provided between a first conductive layer and a second conductive layer, and generates a spin torque and inverts a direction of magnetization in the adjustment layer, when current is supplied. A voltage Vb applied to the magnetic flux control layer is lower than a voltage Vba represented by an expression (1), Vba=Vb0?a×1/log(t)×log(RH)×log(PO2).

Abstract: A magnetic disk device includes a disk, a head comprising a main magnetic pole and a write shield, and configured to generate a magnetic field from the main magnetic pole to the write shield to write data onto the disk, an assist element configured to assist the writing by generating a magnetic field or heating a surface of the disk, and a controller configured to control the head to write the data according to either a first recording method using the assist element or a second recording method not using the assist element depending on a condition of the assist element.

Abstract: According to one embodiment, a magnetic disk device includes a disk, a head including a main magnetic pole having a first end and a second end opposite to the first end in a radial direction of the disk, a write shield facing the main magnetic pole with a gap, and an assist element provided in the gap and at a position where a first distance between the first end and the assist element and a second distance between the second end and the assist element are different from each other, and a controller which controls a voltage applied to the assist element according to a shingled write direction in which a second track is overwritten on a first track.

Abstract: A magnetic disk device includes a disk, a head comprising a main magnetic pole and a write shield, and configured to generate a magnetic field from the main magnetic pole to the write shield to write data onto the disk, an assist element configured to assist the writing by generating a magnetic field or heating a surface of the disk, and a controller configured to control the head to write the data according to either a first recording method using the assist element or a second recording method not using the assist element depending on a condition of the assist element.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic head, a magnetic disk on which a servo pattern used to position the magnetic head when data is to be recorded by means of the magnetic head is recorded, and a control section configured to set a recording condition for each predetermined unit of the magnetic disk on the basis of the servo pattern, and carry out recording of data on the magnetic disk according to the set recording condition.

Abstract: According to one embodiment, a magnetic recording head includes a main magnetic pole which applies a recording magnetic field to a magnetic recording medium, an auxiliary magnetic pole which faces the main magnetic pole across a recording gap, a first magnetic bypass layer which is provided in a recording gap in a track direction, and a second magnetic bypass layer which is provided in the recording gap in the track direction and is arranged at a distance from the first magnetic bypass layer in a track width direction.

Abstract: A magnetic head includes a main magnetic pole, a write shield separated from the main magnetic pole by a write gap, a first side shield that is separated from the main magnetic pole by a first side gap, a second side shield that is separated from the main magnetic pole by a second side gap, a first layer that has a first magnetic relative permeability and is disposed in the write gap between the main magnetic pole and the write shield, and a second layer that has a second magnetic relative permeability and is disposed in the first side gap and the second side gap, wherein the first magnetic relative permeability is smaller than the second magnetic relative permeability.

Abstract: According to one embodiment, a magnetic recording head includes a main magnetic pole which applies a recording magnetic field to a magnetic recording medium, an auxiliary magnetic pole which faces the main magnetic pole across a recording gap, a first magnetic bypass layer which is provided in a recording gap in a track direction, and a second magnetic bypass layer which is provided in the recording gap in the track direction and is arranged at a distance from the first magnetic bypass layer in a track width direction.

Abstract: A magnetic head includes a main magnetic pole, a write shield separated from the main magnetic pole by a write gap, a first side shield that is separated from the main magnetic pole by a first side gap, a second side shield that is separated from the main magnetic pole by a second side gap, a first layer that has a first magnetic relative permeability and is disposed in the write gap between the main magnetic pole and the write shield, and a second layer that has a second magnetic relative permeability and is disposed in the first side gap and the second side gap, wherein the first magnetic relative permeability is smaller than the second magnetic relative permeability.

Abstract: According to one embodiment, a magnetic recording head includes a main magnetic pole which applies a recording magnetic field to a magnetic recording medium, an auxiliary magnetic pole which faces the main magnetic pole across a recording gap, a first magnetic bypass layer which is provided in a recording gap in a track direction, and a second magnetic bypass layer which is provided in the recording gap in the track direction and is arranged at a distance from the first magnetic bypass layer in a track width direction.

Abstract: According to one embodiment, a magnetic recording and reproducing device includes a magnetic flux control layer provided between a main magnetic pole and an auxiliary magnetic pole, and a protective layer provided on an ABS of the auxiliary magnetic pole. The magnetic flux control layer includes an adjustment layer formed of a magnetic material includes one of Fe, Co or Ni and provided between a first conductive layer and a second conductive layer, and generates a spin torque and inverts a direction of magnetization in the adjustment layer, when current is supplied. A voltage Vb applied to the magnetic flux control layer is lower than a voltage Vba represented by an expression (1).

Abstract: According to one embodiment, a magnetic recording head includes a main magnetic pole which applies a recording magnetic field to a magnetic recording medium, an auxiliary magnetic pole which faces the main magnetic pole across a recording gap, a first magnetic bypass layer which is provided in a recording gap in a track direction, and a second magnetic bypass layer which is provided in the recording gap in the track direction and is arranged at a distance from the first magnetic bypass layer in a track width direction.

Abstract: According to one embodiment, a magnetic disk device conforming to perpendicular magnetic recording includes a magnetic disk, a recording head, and a controller. The head includes a main magnetic pole, a return magnetic pole, a recording coil, and a conductive member in which end surfaces are connected to opposed surfaces of a write gap which is opposed to a distal portion of the main magnetic pole and a distal portion of the return magnetic pole, and a resistance value varies. The controller applies a current to the recording coil to excite the magnetic flux in the recording operation, and applies a current at a constant voltage to the magnetic circuit via the comductive member.

Abstract: A magnetic recording apparatus includes a disk-shaped recording medium with a magnetic recording layer, and a recording head that magnetically writes data onto the magnetic recording layer and includes a main magnetic pole, a write shield facing the main magnetic pole and positioned with a writing gap disposed between the main magnetic pole and the write shield, and a magnetic flux control layer disposed inside the write gap between the main magnetic pole and the writing shield. The magnetic flux control layer includes a first layer including a first metal and contacting one of the main magnetic pole and the writing shield, a second control layer, and a third layer including a second metal and contacting the other one of the main magnetic pole and the writing shield. The second control layer includes a magnetic metal and contacts the first layer and the third layer.

Abstract: A magnetic recording apparatus includes a disk-shaped recording medium with a magnetic recording layer, and a recording head that magnetically writes data onto the magnetic recording layer and includes a main magnetic pole, a write shield facing the main magnetic pole and positioned with a writing gap disposed between the main magnetic pole and the write shield, and a magnetic flux control layer disposed inside the write gap between the main magnetic pole and the writing shield. The magnetic flux control layer includes a first layer including a first metal and contacting one of the main magnetic pole and the writing shield, a second control layer, and a third layer including a second metal and contacting the other one of the main magnetic pole and the writing shield. The second control layer includes a magnetic metal and contacts the first layer and the third layer.

Abstract: According to one embodiment, a magnetic head includes a magnetic pole having a first surface, a first shield separated from the magnetic pole along the first surface, and a stacked body provided between the magnetic pole and the first shield. The stacked body includes a magnetic layer, and first and second conductive layers. The magnetic layer includes at least one selected from the group consisting of Fe, Co, and Ni. The first conductive layer contacts the magnetic pole and the magnetic layer, and is provided between the magnetic pole and the magnetic layer. The second conductive layer contacts the magnetic layer and the first shield, is provided between the magnetic layer and the first shield. The first shield has a first shield surface contacting the second conductive layer. A ratio of a length of the magnetic layer to a length of the first shield surface is 0.1 or more.

Abstract: According to one embodiment, a magnetic head includes a magnetic pole having a first surface, a first shield separated from the magnetic pole along the first surface, and a stacked body provided between the magnetic pole and the first shield. The stacked body includes a magnetic layer, and first and second conductive layers. The magnetic layer includes at least one selected from the group consisting of Fe, Co, and Ni. The first conductive layer contacts the magnetic pole and the magnetic layer, and is provided between the magnetic pole and the magnetic layer. The second conductive layer contacts the magnetic layer and the first shield, is provided between the magnetic layer and the first shield. The first shield has a first shield surface contacting the second conductive layer. A ratio of a length of the magnetic layer to a length of the first shield surface is 0.1 or more.

Abstract: A magnetic head includes a main magnetic pole, a write shield separated from the main magnetic pole by a write gap, a first side shield that is separated from the main magnetic pole by a first side gap, a second side shield that is separated from the main magnetic pole by a second side gap, a first layer that has a first magnetic relative permeability and is disposed in the write gap between the main magnetic pole and the write shield, and a second layer that has a second magnetic relative permeability and is disposed in the first side gap and the second side gap, wherein the first magnetic relative permeability is smaller than the second magnetic relative permeability.

Abstract: According to one embodiment, a magnetic disk device conforming to perpendicular magnetic recording includes a magnetic disk, a recording head, and a controller. The head includes a main magnetic pole, a return magnetic pole, a recording coil, and a conductive member in which end surfaces are connected to opposed surfaces of a write gap which is opposed to a distal portion of the main magnetic pole and a distal portion of the return magnetic pole, and a resistance value varies. The controller applies a current to the recording coil to excite the magnetic flux in the recording operation, and applies a current at a constant voltage to the magnetic circuit via the comductive member.