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, a recording unit, and a reproducing unit. The magnetic recording medium includes a first track including first and second sub-tracks extending in a first direction. The second sub-track is arranged with the first sub-track in a second direction intersecting the first direction. The recording unit records information in the first and second sub-tracks. The reproducing unit reproduces the information recorded in the first and second sub-tracks while opposing the first, second sub-tracks, and a boundary between the first and second sub-tracks. The first sub-track includes first magnetic recording components including first and second components. The second sub-track includes second magnetic recording components including third and fourth components. A first recording symbol is formed of the first and third components. A second recording symbol is formed of the second and fourth components.

Abstract: According to one embodiment, a microwave-assisted magnetic head includes a main magnetic pole configured to apply a recording magnetic field to a magnetic recording medium, an auxiliary magnetic pole configured to constitute a magnetic circuit together with the main magnetic pole, and a domain propagation element including a domain propagation path having two ends and a magnetic anisotropy perpendicular to a domain propagation direction, and a domain input portion configured to write a magnetic domain in the domain propagation path, and a current supply mechanism connected to the domain propagation path, and at least part of the domain propagation path passes between the main magnetic pole and the auxiliary magnetic pole.

Abstract: A magnetic recording head includes a main magnetic pole in which a recording magnetic field is generated, a write shield magnetic pole disposed alongside the main magnetic pole with a gap therebetween, a spin torque oscillator disposed within the gap and configured to generate a microwave, an anti-ferromagnetic layer disposed within the gap between the write shield magnetic pole and the spin torque oscillator, and a non-magnetic metal layer disposed within the gap between the spin torque oscillator and the anti-ferromagnetic layer.

Abstract: According to one embodiment, a magnetic recording head records information in a magnetic recording medium by shingled magnetic recording. The magnetic recording head includes a magnetic pole and a shield opposing the magnetic pole. The magnetic pole has a shield-opposing surface opposing the shield. The shield-opposing surface includes a first portion and a second portion. A position of the second portion in a track width direction is different from a position of the first portion in the track width direction, the track width direction intersecting a first direction from the magnetic pole toward the shield. The first portion records the information in the magnetic recording medium after the second portion in the shingled magnetic recording. A first distance between the first portion and the shield is shorter than a second distance between the second portion and the shield. The shield-opposing surface is tilted with respect to the first 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 including first and second sub-tracks extending in a first direction. The second sub-track is arranged with the first sub-track in a second direction intersecting the first direction. The recording unit records information in the first and second sub-tracks. The reproducing unit reproduces the information recorded in the first and second sub-tracks while opposing the first, second sub-tracks, and a boundary between the first and second sub-tracks. The first sub-track includes first magnetic recording components including first and second components. The second sub-track includes second magnetic recording components including third and fourth components. A first recording symbol is formed of the first and third components. A second recording symbol is formed of the second and fourth components.

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 microwave assisted magnetic head includes a spin torque oscillator, and if driving current of the spin torque oscillator is zero, a magnetization direction of the spin injection layer is identical regardless of polarity of recording current, and if the driving current of the spin torque oscillator is not zero, the magnetization direction of the spin injection layer changes in response to the polarity of the recording current.

Abstract: According to one embodiment, a magnetic recording head includes a main pole configured to apply a recording magnetic field to a recording layer of a recording medium, a trailing shield opposed to the main pole with a write gap therebetween, and a high-frequency oscillator between the main pole and the trailing shield in a range of a width of the main pole in a track width direction, and configured to generate a high-frequency magnetic field. The high-frequency oscillator includes a spin injection layer, an intermediate layer, and an oscillation layer, and at least the oscillation layer comprises divided oscillation regions.

Abstract: A magnetic head according to an embodiment includes: a non-local 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 head includes a main pole configured to apply a recording magnetic field to a recording layer of a recording medium, a trailing shield opposed to the main pole with a write gap therebetween, and a high-frequency oscillator between the main pole and the trailing shield in a range of a width of the main pole in a track width direction, and configured to generate a high-frequency magnetic field. The high-frequency oscillator includes a spin injection layer, an intermediate layer, and an oscillation layer, and at least the oscillation layer comprises divided oscillation regions.

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: A magnetic head of an embodiment has first and second magnetic shields, a stack, a side shield, and an antiferromagnetic layer. The stack has a pin layer, a nonmagnetic layer, and first and second free layers. The second free layer is antiferromagnetically exchange coupled to the first free layer and is exchange coupled to the antiferromagnetic layer. The side shield is exchange coupled to the antiferromagnetic layer.

Abstract: A magnetic head of an embodiment includes: a first electrode being a magnetic body having a magnetic shielding property; a first signal detector disposed on the first electrode and being a differential magnetoresistive effect element; a second electrode disposed on the first signal detector; an insulating layer disposed on the second electrode; a third electrode disposed on the insulating layer; a second signal detector disposed on the third electrode and being a differential magnetoresistive effect element; and a fourth electrode disposed on the second signal detector and being a magnetic body having a magnetic shielding property. At least one of the second electrode and the third electrode is a nonmagnetic metal.

Abstract: According to one embodiment, a magnetic recording head records information in a magnetic recording medium by shingled magnetic recording. The magnetic recording head includes a magnetic pole and a shield opposing the magnetic pole. The magnetic pole has a shield-opposing surface opposing the shield. The shield-opposing surface includes a first portion and a second portion. A position of the second portion in a track width direction is different from a position of the first portion in the track width direction, the track width direction intersecting a first direction from the magnetic pole toward the shield. The first portion records the information in the magnetic recording medium after the second portion in the shingled magnetic recording. A first distance between the first portion and the shield is shorter than a second distance between the second portion and the shield. The shield-opposing surface is tilted with respect to the first direction.

Abstract: An optical temperature sensor includes an light-emitting-side measurement unit to measure a first light intensity of a measuring beam and a second light intensity of a reference beam, and a light-receiving-side measurement unit to measure a third light intensity of a first reflected beam of the measuring beam and a fourth light intensity of a second reflected beam of the reference beam. The optical temperature sensor further includes a control unit to adjust at least one of a first control target value of the first light intensity and a second control target value of the second light intensity based on at least one of the third light intensity and the fourth light intensity. The control unit controls at least one of the first light intensity and the second light intensity based on the adjusted at least one of the first and second control target values.

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: A magnetic recording and reproducing device according to an embodiment includes a magnetic recording medium and a controller. The magnetic recording medium includes in sequence a substrate, a storage layer, an exchange layer, and a surface recording layer. The controller executes following steps (1) to (6): (1) magnetically recording first information on the surface recording layer; (2) transferring the first information recorded on the surface recording layer to the storage layer; (3) magnetically recording second information on the surface recording layer; (4) magnetically reproducing the second information from the surface recording layer; (5) transferring the first information recorded on the storage layer to the surface recording layer; and (6) magnetically reproducing the first information transferred to the surface recording layer.

Abstract: A magnetic recording head includes a main magnetic pole in which a recording magnetic field is generated, a write shield magnetic pole disposed alongside the main magnetic pole with a gap therebetween, a spin torque oscillator disposed within the gap and configured to generate a microwave, an anti-ferromagnetic layer disposed within the gap between the write shield magnetic pole and the spin torque oscillator, and a non-magnetic metal layer disposed within the gap between the spin torque oscillator and the anti-ferromagnetic layer.

Abstract: According to one embodiment, a magnetic recording head includes a main pole configured to apply a recording magnetic field to a recording layer of a recording medium, a trailing shield opposed to the main pole with a write gap therebetween, and a high-frequency oscillator between the main pole and the trailing shield in a range of a width of the main pole in a track width direction, and configured to generate a high-frequency magnetic field. The high-frequency oscillator includes a spin injection layer, an intermediate layer, and an oscillation layer, and at least the oscillation layer comprises divided oscillation regions.