Abstract: According to one embodiment, a magnetic recording head includes a magnetic pole, a stacked body, and a first nonmagnetic layer. The stacked body includes first magnetic layer, a second magnetic layer provided between the first magnetic layer and the magnetic pole, and an intermediate layer provided between the first magnetic layer and the second magnetic layer and being nonmagnetic. The first nonmagnetic layer is provided between the second magnetic layer and the magnetic pole. A product of a thickness and a saturation magnetic flux density of the second magnetic layer is larger than a product of a thickness and a saturation magnetic flux density of the first magnetic layer. The length of the first magnetic layer is shorter than a length of the second magnetic layer. A current flows from the second magnetic layer toward the first magnetic layer.

Abstract: According to one embodiment, there is provided a spin torque oscillator including an oscillation layer formed of a magnetic material, a spin injection layer formed of a magnetic material and configured to inject a spin into the oscillation layer, and a current confinement layer including an insulating portion formed of an oxide or a nitride and a conductive portion formed of a nonmagnetic metal and penetrating the insulating portion in a direction of stacking. The conductive portion of the current confinement layer is positioned near a central portion of a plane of a device region including the oscillation layer and the spin injection layer.

Abstract: According to one embodiment, a magnetic recording head includes a magnetic pole and a shield. The shield has a first opposing surface opposing the magnetic pole. The first opposing surface includes a first opposing portion. The magnetic pole and the first opposing portion overlap in a first direction from the magnetic pole toward the shield. The first opposing portion includes a first protrusion.

Abstract: According to one embodiment, a magnetic recording head includes a magnetic pole, a stacked body, and a first non-magnetic layer. The stacked body includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the magnetic pole, and a non-magnetic intermediate layer provided between the first magnetic layer and the second magnetic layer. The first non-magnetic layer is provided between the second magnetic layer and the magnetic pole, and contacts the magnetic pole and the second magnetic layer. The first magnetic layer has a first thickness and a first saturation magnetic flux density. The second magnetic layer has a second thickness and a second saturation magnetic flux density. A second product of the second thickness and the second saturation magnetic flux density is larger than a first product of the first thickness and the first saturation magnetic flux density.

Abstract: A temperature measurement device includes a light emitting part including a first light source configured to output measurement light with a first wavelength and a second light source configured to output reference light with a second wavelength, a light receiving part configured to receive reflected light of the measurement light and reflected light of the reference light that have passed through a temperature sensing device that changes light transmission characteristics with changes in temperature, a control part configured to measure a temperature detected by the temperature sensing device based on an amount of light of the received reflected light of the measurement light and an amount of light of the received reflected light of the reference light, and a temperature adjustment part configured to separately adjust the temperature of the first light source and the temperature of the second light source.

Abstract: A magnetic head according to an embodiment includes: a spin valve element with three terminals including a nonmagnetic base layer, a first terminal including a first magnetic layer, a second terminal including a second magnetic layer, and a third terminal including a third magnetic layer; and a slider including a first external lead terminal connecting to the first terminal, a second external lead terminal connecting to the second terminal, and a third external lead terminal connecting to the third terminal, in an operation, a first current being caused to flow from the second external lead terminal to the third terminal via the second terminal and the nonmagnetic base layer, and a second current that is lower than the first current being caused to flow to the first terminal.

Abstract: According to one embodiment, a magnetic recording device includes a magnetic recording medium and a magnetic head. The magnetic head includes a magnetic pole and a trailing shield. The magnetic pole has a medium-opposing surface opposing the magnetic recording medium. The medium-opposing surface has a magnetic pole length along a first direction. The first direction is from the magnetic pole toward the trailing shield. The magnetic pole length is shorter than a track pitch of the magnetic recording medium.

Abstract: A microwave-assisted magnetic recording head according to an embodiment includes: a magnetic pole; a magnetic shield including a first portion and a second portion connecting to the first portion, a gap being present between the first portion and the magnetic pole; a recording coil disposed to at least one of the magnetic pole and the magnetic shield; and a spin torque oscillator including a nonmagnetic intermediate layer extending within and outside the gap, an oscillation layer disposed on a portion of the nonmagnetic intermediate layer in the gap, and a spin injection layer in which a magnetization direction is pinned and which is disposed on a portion of the nonmagnetic intermediate layer outside the gap so as to be separated from the oscillation layer.

Abstract: According to one embodiment, a magnetic recording and reproducing device includes a magnetic recording medium including a plurality of recording tracks, a magnetic head, and a controller. The plurality of recording tracks includes a first track. The controller causes the magnetic head to implement a first recording operation of recording first information in at least two of a plurality of first track recording components included in the first track. The controller causes the magnetic head to implement a first reproduction operation of reproducing the first information from a first information reproducing/recording component of one of the at least two of the plurality of first track recording components.

Abstract: According to one embodiment, a magnetic recording and reproducing device includes a magnetic recording medium and a magnetic head. The magnetic recording medium includes a first track including a first sub-track extending along a first direction, and a second sub-track extending along the first direction. The second sub-track is arranged with the first sub-track in a second direction intersecting the first direction. The magnetic head includes a recording unit and a reproducing unit. The recording unit records information in the magnetic recording medium. The reproducing unit reproduces the information recorded in the magnetic recording medium. The recording unit includes a magnetic pole, a write shield separated from the magnetic pole in the first direction, and a side shield separated from the magnetic pole in the second direction. The reproducing unit includes a reproducing element having a reproducing width along the second direction.

Abstract: According to one embodiment, a magnetic recording and reproducing device includes a magnetic recording medium, a recording unit and a reproducing unit. The magnetic recording medium includes a first track and a second track, the first track extending in a first direction, the second track extending in the first direction and being arranged with the first track in a second direction intersecting the first direction. The first track includes first and second sub-tracks extending in the first direction. The second track includes third and fourth sub-tracks extending in the first direction. The second sub-track is disposed between the first and fourth sub-tracks. The third sub-track is disposed between the second and fourth sub-tracks. The recording unit records information in the first and second tracks. The reproducing unit reproduces first information recorded in the first track. The reproducing unit reproduces second information recorded in the second track.

Abstract: According to one embodiment, a magnetic recording head includes a magnetic pole and a shield. The shield has a first opposing surface opposing the magnetic pole. The first opposing surface includes a first opposing portion. The magnetic pole and the first opposing portion overlap in a first direction from the magnetic pole toward the shield. The first opposing portion includes a first protrusion.

Abstract: Provided is an optical temperature sensor including a temperature sensing element having light transmission characteristics that vary with temperature, a hollow holding member that holds the temperature sensing element, and an optical fiber that is arranged inside the holding member, the optical fiber including a tip face that is disposed to face the temperature sensing element at a position separated from the temperature sensing element by a predetermined distance. The temperature sensing element allows light emitted from the tip face of the optical fiber to be incident thereon, allows the incident light to be transmitted therethrough, and allows reflected light of the transmitted light that has been reflected by a measuring object to be transmitted therethrough.

Abstract: A magnetic head of an embodiment includes a stack, side shields, and a first and a second magnetic shield. The stack includes a pin layer having a fixed magnetization direction, a first free layer having a magnetization direction to change in accordance with an external magnetic field, a second free layer antiferromagnetically exchange-coupled with the first free layer and having a magnetization direction to change in accordance with the field, and an antiferromagnetic layer exchange-coupled with the second free layer. A magnetic field is applied from the side shields to the first and second free layers, and a direction of the magnetic field is substantially parallel to the magnetization direction of one of the first and second free layers and substantially antiparallel to the magnetization direction of the other, and a magnetic volume of the one is larger than a magnetic volume of the other.

Abstract: According to one embodiment, a magnetic recording head includes an air bearing surface, a magnetic pole having a distal end portion, a write shield opposed to the distal end portion of the magnetic pole across a write gap, and a high-frequency oscillator between the magnetic pole and the write shield in the write gap. The high-frequency oscillator includes a spin injection layer, an intermediate layer and an oscillation layer which are stacked in a head travel direction. A film thickness of the spin injection layer in the head travel direction at a height position away from the air bearing surface is greater than a film thickness of the spin injection layer in the head travel direction on the air bearing surface.

Abstract: The problem addressed by the present invention is to increase the use efficiency of a holographic storage medium, achieving an increase in the number of storage layers, and to achieve favorable and stable storage maintaining the storage quality of each pixel of a page interior and page exterior. As a solution, the present invention is provided with: a phase mask that adds phase information to signal light; a phase mask drive unit that drives the phase mask; a phase mask control unit that controls the phase mask drive unit; and a phase mask drive speed detection unit that detects the drive speed of the phase mask. When the phase mask drive speed obtained by the phase mask drive speed detection unit is contained within a predetermined range, the storage of information is executed.

Abstract: According to one embodiment, a magnetic recording and reproducing device includes a magnetic recording medium, a recording unit and a reproducing unit. The magnetic recording medium includes a first track and a second track, the first track extending in a first direction, the second track extending in the first direction and being arranged with the first track in a second direction intersecting the first direction. The first track includes first and second sub-tracks extending in the first direction. The second track includes third and fourth sub-tracks extending in the first direction. The second sub-track is disposed between the first and fourth sub-tracks. The third sub-track is disposed between the second and fourth sub-tracks. The recording unit records information in the first and second tracks. The reproducing unit reproduces first information recorded in the first track. The reproducing unit reproduces second information recorded in the second track.

Abstract: A hologram reproducing device which reproduces information from a recording medium having information recorded by interfering a signal beam and a reference beam, provided with a first light-angle change unit which changes an irradiation angle of the reference beam; a second light-angle change unit which changes the irradiation angle of the reference beam; a photodetector which detects a reproduction beam; a first light-angle drive-signal output unit which outputs a drive signal of the first light-angle change unit; a first light-angle control unit which controls the first light-angle change unit on the basis of the output of the photodetector; a second light-angle drive-signal output unit which outputs a drive signal of the second light-angle change unit; a second light-angle control unit which controls the second light-angle change unit; and a light-angle interpolation processing unit which controls a control target value of the second light-angle control unit.

Abstract: According to one embodiment, a magnetic recording and reproducing device includes a magnetic recording medium and a magnetic head. The magnetic recording medium includes a first track including a first sub-track extending along a first direction, and a second sub-track extending along the first direction. The second sub-track is arranged with the first sub-track in a second direction intersecting the first direction. The magnetic head includes a recording unit and a reproducing unit. The recording unit records information in the magnetic recording medium. The reproducing unit reproduces the information recorded in the magnetic recording medium. The recording unit includes a magnetic pole, a write shield separated from the magnetic pole in the first direction, and a side shield separated from the magnetic pole in the second direction. The reproducing unit includes a reproducing element having a reproducing width along the second direction.

Abstract: An example magnetic recording apparatus includes a magnetic recording medium, a magnetic recording head and a signal processor. The magnetic recording head includes a first magnetic pole to apply a recording magnetic field to the magnetic recording medium; a spin torque oscillator arranged parallel to the first magnetic pole; and a first coil to magnetize the first magnetic pole. The signal processor writes and reads a signal on the magnetic recording medium by using the magnetic recording head and includes a first current circuit to supply a recording current to the first coil, the recording current including a recording signal to be recorded on the magnetic recording medium. The recording current includes either one of a signal changing at a frequency higher than that of the recording signal, and a signal having the same frequency as the recording signal and changing an absolute value thereof in one cycle.