摘要:
A magnetic sensor includes a magnetoresistance element having a peak of a thermal fluctuation strength of magnetization under a magnetic field having a certain frequency, a frequency filter connected to the magnetoresistance element and having its transmittance decreased or increased in substantially the frequency of the magnetic field to output a signal corresponding substantially to the peak of the thermal fluctuation strength of magnetization, and a detector connected to the frequency filter to detect the magnetic field based on the signal of the frequency filter.
摘要:
Some spin tunnel transistors with a larger current transmittance and a higher MR ratio are described. One of the spin tunnel transistor comprises a collector; an emitter; abase formed between the collector and the emitter, including a first ferromagnetic metal layer variable in its magnetization under an external magnetic field; a barrier layer formed between the first ferromagnetic metal layer and one of the collector and the emitter, the other of the collector and the emitter including a semiconductor crystal layer; and a transition metal silicide crystal layer between the semiconductor crystal layer and the base. The transition metal silicide crystal layer may be replaced with a palladium layer, a transition metal nitride layer, or a transition metal carbide layer.
摘要:
A magnetic sensor has a three-terminal magnetic device consisting of an emitter, a base, and a collector. A semiconductor layer serving as the collector and a magnetic multilayered film serving as the base form a Schottky junction. The magnetic multilayered film has two magnetic films opposing each other with a nonmagnetic film between them. The emitter constructed of a metal film and the base are connected via a tunnel insulating film. The relationship between the magnetization directions in the magnetic films changes in accordance with an external magnetic field, and this changes the value of a current flowing through the magnetic device. The external magnetic field is sensed on the basis of this change in the current value.
摘要:
A magnetic head according to an embodiment includes: a spin-torque oscillator comprising a first ferromagnetic layer, a second ferromagnetic layer, a third ferromagnetic layer provided on the opposite side of the second ferromagnetic layer from the first ferromagnetic layer, a first nonmagnetic layer provided between the first ferromagnetic layer and the second ferromagnetic layer, a second nonmagnetic layer provided between the second ferromagnetic layer and the third ferromagnetic layer, a first electrode provided on a surface on the opposite side of the first ferromagnetic layer from the first nonmagnetic layer, and a second electrode provided on a surface on the opposite side of the third ferromagnetic layer from the second nonmagnetic layer. Magnetization precession is induced in each of the first through third ferromagnetic layers when current is applied between the first and second electrodes.
摘要:
According to one embodiment, a reproducing head includes a spin-torque oscillator and a pair of shield parts. The spin-torque oscillator has a first surface facing a magnetic recording medium. The pair of shield parts each has a second surface facing the magnetic recording medium, the spin-torque oscillator being arranged between the shield parts. A distance between the second surface and the magnetic recording medium is shorter than a distance between the first surface and the magnetic recording medium.
摘要:
According to one embodiment, a high-frequency magnetic field generation element includes a first fixed layer, a first free layer, and a second free layer. A direction of a magnetization of the first fixed layer is fixed and has a component parallel to a first direction. A direction of a magnetization of the first free layer is variable and has a component orthogonal to the first direction. A direction of a magnetization of the second free layer is variable and has a component orthogonal to the first direction. The first fixed layer is provided between the first free layer and the second free layer. The magnetizations of the first free layer and the second free layer oscillate. A rotation direction of the magnetization of the first free layer is opposite to a rotation direction of the magnetization of the second free layer.
摘要:
According to one embodiment, a magnetic medium includes at least one recording layer including a first magnetic layer, a second magnetic layer and a non-magnetic layer. The first magnetic layer is form of a first magnetic material having a first magnetic anisotropy. The second magnetic layer is made of a second magnetic material having a second magnetic anisotropy different from the first magnetic anisotropy. The non-magnetic layer is made of a non-magnetic material and between the first and second magnetic layers, the first magnetic layer and the second magnetic layer being coupled such that directions of magnetization of the first and second magnetic layers are opposed to each other.
摘要:
A magnetic oscillation element includes a magnetization fixing layer whose magnetization direction is substantially pinned toward one direction, a nonmagnetic layer that is disposed on the magnetization fixing layer, and a magnetization free layer whose magnetization direction fluctuates. The magnetization free layer is disposed on the nonmagnetic layer. A pair of electrodes apply a current in a direction perpendicular to the film surface of the magnetization fixing layer, the nonmagnetic layer, and the magnetization free layer. The magnetization free layer is excited with a magnetization vibration caused by spin transfer from the magnetization fixing layer due to the appliance of the current.
摘要:
A magnetic recording and reproducing apparatus includes a magnetic head that has a spin-torque oscillator and a magnetic disk and the spin-torque oscillator detects a magnetic field from the magnetic disk and outputs a signal. A criterion used to determine the rotational speed of the magnetic disk, the frequency shift of the spin-torque oscillator produced by a magnetic field from the magnetic disk, a characteristic oscillation frequency of the spin-torque oscillator and the full-width at half maximum of an oscillation spectrum is given in order for a read signal output from the spin-torque oscillator to satisfy a desired signal-to-noise ratio and a magnetic recording and reproducing apparatus is configured based on the criterion.
摘要:
A magnetic recording head includes a spin wave oscillator having a lamination film including a first magnetic layer and a second magnetic layer, and a pair of electrodes adapted to inject a current between the first magnetic layer and the second magnetic layer to generate a spin wave in one of the first magnetic layer and the second magnetic layer; and a recording magnetic pole provided on one side with the spin wave oscillator, the spin wave oscillator locally heating the recording track prior to recording by the recording magnetic pole.