Abstract: According to one embodiment, a magnetic disk device comprises an actuator configured to drive a head stack assembly including a plurality of magnetic heads, a preamplifier connected to each of the magnetic heads with a plurality of traces, and a control section configured to control read/write of the plurality of magnetic heads from/to the magnetic disk through the preamplifier. While a first magnetic head among the plurality of magnetic heads executes a write operation, the control section interrupts access of a second magnetic head in proximity to the first magnetic head to the magnetic disk.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, a control unit, and a setting unit. The magnetic head includes a write element which writes data to the magnetic disk and heater elements which adjust a levitation amount relative to the magnetic disk. The setting unit sets a heater value to be set on the basis of a measurement result of measuring the recording quality of the data written to the magnetic disk. The control unit controls electric power to be supplied to the heater elements on the basis of the heater value to be set to the setting unit.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, a control unit, and a setting unit. The magnetic head includes a write element which writes data to the magnetic disk and heater elements which adjust a levitation amount relative to the magnetic disk. The setting unit sets a heater value to be set on the basis of a measurement result of measuring the recording quality of the data written to the magnetic disk. The control unit controls electric power to be supplied to the heater elements on the basis of the heater value to be set to the setting unit.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head configured to write data on the magnetic disk, an assist section configured to assist, when the magnetic head writes data on the magnetic disk, write of the data by utilizing an assist element, a voltage control section configured to control a voltage to be applied to the assist element, and a positioning control section configured to carry out positioning of the magnetic head relatively to the magnetic disk on the basis of servo data and acquire positional error data of the magnetic head positioned on the basis of the servo data. The voltage control section adjusts the voltage to be applied to the assist element on the basis of the positional error data.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head configured to write data on the magnetic disk, an assist section configured to assist, when the magnetic head writes data on the magnetic disk, write of the data by utilizing an assist element, a voltage control section configured to control a voltage to be applied to the assist element, and a positioning control section configured to carry out positioning of the magnetic head relatively to the magnetic disk on the basis of servo data and acquire positional error data of the magnetic head positioned on the basis of the servo data. The voltage control section adjusts the voltage to be applied to the assist element on the basis of the positional error data.

Abstract: According to one embodiment, a magnetic disk device comprises an actuator configured to drive a head stack assembly including a plurality of magnetic heads, a preamplifier connected to each of the magnetic heads with a plurality of traces, and a control section configured to control read/write of the plurality of magnetic heads from/to the magnetic disk through the preamplifier. While a first magnetic head among the plurality of magnetic heads executes a write operation, the control section interrupts access of a second magnetic head in proximity to the first magnetic head to the magnetic disk.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head including an assist part to assist recording of data into the magnetic disk, a controller configured to control the recording of data by the magnetic head based on a recording condition, and a memory configured to record a first threshold value used to define that an assist element included in the assist part is in a deterioration condition. Furthermore, the controller detects the condition of the assist element, determines whether or not the recording condition is changed based on the detected condition and the first threshold value stored in the memory, and changes the recording condition based on the result of the determination.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head including an assist part to assist recording of data into the magnetic disk, a controller configured to control the recording of data by the magnetic head based on a recording condition, and a memory configured to record a first threshold value used to define that an assist element included in the assist part is in a deterioration condition. Furthermore, the controller detects the condition of the assist element, determines whether or not the recording condition is changed based on the detected condition and the first threshold value stored in the memory, and changes the recording condition based on the result of the determination.

Abstract: According to one embodiment, a recording head includes a main pole and a first shield. The first shield includes a distal end portion projecting from an air bearing surface of a slider. The distal end portion includes a distal end surface which includes a first shield edge opposing the main pole with a write gap and a second shield edge spaced apart from the first shield edge in a trailing end side. A distal end portion of the main pole projects from the distal end surface. When a length between the distal end portion of the main pole and the second shield edge is L1, the projection amount of the distal end portion of the main pole is h2, a flying pitch is D1, and a protrusion pitch angle is D2, the recording head satisfies a relationship of: L1?h2/(D1+D2).

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a recording head and a controller. The recording head includes a high-frequency oscillator disposed in a write gap between a main magnetic pole and a return magnetic pole and configured to oscillate in accordance with a bias voltage, and a bias voltage supply circuit configured to supply the bias voltage to the high-frequency oscillator. The controller includes a bias voltage controller configured to control the bias voltage to be applied to the high-frequency oscillator in accordance with a sampling frequency of data when the data is recorded on the magnetic disk by the recording head.

Abstract: According to one embodiment, a magnetic disk device applies a bias voltage for measurement to a high frequency assist element according to a setting instruction of the bias voltage to measure a conduction current by in a recording head, calculates the resistance value in the supply path of the bias voltage from a relationship between the measured current and the bias voltage for measurement, and changes the bias voltage applied at the time of data recording based on the calculated resistance value.

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 applies a bias voltage for measurement to a high frequency assist element according to a setting instruction of the bias voltage to measure a conduction current by in a recording head, calculates the resistance value in the supply path of the bias voltage from a relationship between the measured current and the bias voltage for measurement, and changes the bias voltage applied at the time of data recording based on the calculated resistance value.

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 includes a magnetic disk, a recording head and a controller. The recording head includes a high-frequency oscillator disposed in a write gap between a main magnetic pole and a return magnetic pole and configured to oscillate in accordance with a bias voltage, and a bias voltage supply circuit configured to supply the bias voltage to the high-frequency oscillator. The controller includes a bias voltage controller configured to control the bias voltage to be applied to the high-frequency oscillator in accordance with a sampling frequency of data when the data is recorded on the magnetic disk by the recording head.

Abstract: According to one embodiment, a magnetic head includes a main pole, a write shield magnetic pole opposed to the main pole with a write gap, and a high-frequency oscillator provided between the main pole and the write shield magnetic pole within the write gap. The main pole includes a shield-side end surface opposing the write shield magnetic pole with the write gap and brought into contact with the high frequency oscillator. The high-frequency oscillator has a width in a cross-track direction, in an air bearing surface, greater than a width of the shield-side end surface in the cross-track direction. The high-frequency oscillator is disposed to extend over at least one end edge of the shield-side end surface in the cross-track direction to an outer side of the main pole.

Abstract: According to one embodiment, a magnetic disk device includes a disk, a head including a write head and a first and a second read head, and a controller configured to generate a correction value based on placement information on the write head and the first and the second read head, a first distance between the first read head and the second read head in a case where the first read head is placed at a first position of the disk, and a second distance between the first read head and the second read head in a case where the first read head is placed at the first position, and to correct positions of the heads based on the correction value in a case where first data written with the first read head placed at the first position is read.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a recording head and a controller configured to control the recording head. The recording head includes a high-frequency oscillator disposed in a write gap formed between a main magnetic pole and a return magnetic pole, and a bias voltage application circuit configured to apply a bias voltage to the high-frequency oscillator. The controller includes a bias voltage controller configured to change a bias voltage to be applied to the high-frequency oscillator in accordance with a sampling frequency of data before the data is recorded on the magnetic disk by the recording head.

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.