Kabushiki Kaisha Toshiba

Toshiba Electronic Devices & Storage Corporation

Gaku Koizumi

Tomoko Taguchi

Masaya Ohtake

Yusuke Tomoda

Akihiko Takeo

Tomoyuki Maeda

Naoyuki Narita

Toru Watanabe

Katsuhiko Koui

Kenichiro Yamada

Takeyori Hara

Naoki Tagami

Masahiro Takashita

Masami Yamane

Mio Okada

According to one embodiment, a magnetic disk device comprises a magnetic head including a main pole, an auxiliary magnetic pole, side shields disposed on both sides of the main pole in a track width direction with a side gap therebetween, a high frequency oscillation element disposed in the write gap between the main pole and the auxiliary magnetic pole, and a magnetic flux control element disposed in the side gap between the main pole and the side shield to control oscillation frequency of the high frequency oscillation element, an oscillation element controller configured to control bias current supplied to the high frequency oscillation element, and a magnetic flux control element controller configured to control bias current supplied to the magnetic flux control element.

Magnetic disk device

According to one embodiment, a magnetic head includes a main pole, an auxiliary magnetic pole provided with a write gap in the main pole, a spin torque control element provided in the write gap, a bias current control portion which supplies a bias current to the spin torque control element, and a resistance measuring portion which measures a resistance value of the spin torque control element. The absolute value of a difference between a first resistance value when a bias current is applied with a polarity that magnetization of the spin torque control element is reversed and a second resistance value when the bias current is applied to a reversed polarity of the polarity is less than or equal to 4%.

Magnetic head and magnetic recording/reproducing device

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.

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.

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.

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 L, the projection amount of the distal end portion of the main pole is h, a flying pitch is D, and a protrusion pitch angle is D, the recording head satisfies a relationship of: L&#x2265;h/(D+D).

Magnetic head and disk device with heat actuators

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.

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.

Magnetic recording device capable of stabilizing oscillations of high frequency assisted element

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.

Magnetic head and disk device having gap layers with different magnetic relative permeabilities

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.

Magnetic head with high-frequency oscillating element and disk device comprising the same

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.

Method for correcting position offset of the heads on two dimensional magnetic recording device

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.

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.

Magnetic disk device which controls a recording operation and a non-recording operation of a recording head and a recording head control method of the magnetic disk device

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.

Magnetic recording apparatus

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.

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Yokohama Kanagawa, Japan

Gaku Koizumi