摘要:
According to one embodiment, a spin-torque oscillator includes a non-magnetic unit, one or more first magnetic unit, and a second magnetic unit. The non-magnetic unit is formed of a non-magnetic body. The one or more first magnetic unit is connected to the non-magnetic unit and generates a pure spin current indicating the flow of the electron spin that does not accompany an electric charge current. The second magnetic unit is connected to the non-magnetic unit in a manner such that a distance between the second magnetic unit and the first magnetic unit is shorter than a spin diffusion length indicating a distance that an electronic spin polarization is maintained in the non-magnetic unit. The second magnetic unit oscillates by the pure spin current.
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, there is provided a magnetic head for a three-dimensional magnetic recording/reproducing apparatus, the head executing reading from or writing to a recording medium, utilizing a magnetic resonance, the medium including stacked layers formed of magnetic substances having different resonance frequencies, the head comprising a spin torque oscillation unit and auxiliary magnetic poles. The unit is operable to simultaneously oscillate at a plurality of frequencies to cause the magnetic resonance, when reading or writing. The magnetic poles assist the unit, when reading or writing. Further, according to another embodiment, there is provided a recording magnetic head using a high-frequency assist method and comprising a microwave magnetic field applying unit and a recording magnetic pole. The unit executes writing to a recording medium, and is formed of a plurality of spin torque oscillation elements having phases thereof synchronized. The magnetic pole assists the writing.
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, magnetization directions of a magnetic free layer and a magnetic pinned layer are parallel to junction planes between the magnetic free layer and a spacer layer and between the magnetic pinned layer and the spacer layer. The magnetic free layer has a uniaxial magnetic anisotropy, and generates a magnetization oscillation when a current larger than an oscillation threshold current flows through the magnetic free layer. A magnetic field generator controls a magnitude and a direction of an external magnetic field to cancel a shift amount of an oscillation frequency caused by a diamagnetic field due to the magnetization oscillation and a shift amount of the oscillation frequency caused by a magnetic field due to the uniaxial magnetic anisotropy.
摘要:
A spin-tunnel transistor having a tunnel barrier layer formed of an antiferromagnetic material which is exchange coupled with a first or second ferromagnetic metal layer of a base B formed adjoining to the antiferromagnetic material, so as to fix magnetization of the adjoining ferromagnetic layer. The base B includes a nonmagnetic metal layer which is formed between the first and second ferromagnetic metal layers and decouple magnetization coupling between the first and second ferromagnetic metal layers. The base B is formed between a collector and an emitter to form tri-terminal device. Those spin-tunnel transistor may be used as a sensor of a magnetic reproducing head used in a hard disk drive.
摘要:
It is made possible to to provide a spin-torque oscillator that has a high Q value and a high output. A spin-torque oscillator includes: an oscillating field generating unit configured to generate an oscillating field; and a magnetoresistive element including a magnetoresistive effect film including a first magnetization pinned layer of which a magnetization direction is pinned, a first magnetization free layer of which a magnetization direction oscillates with the oscillating field, and a first spacer layer interposed between the first magnetization pinned layer and the first magnetization free layer.
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:
A magnetic element has a first magnetic material exhibiting thermal fluctuation of magnetization which depends on an external magnetic field and generates spin fluctuation in conduction electrons; a nonmagnetic conductive material which is laminated on the first magnetic material and transfers the conduction electrons; a second magnetic material which is laminated on the nonmagnetic conductive material and generates a magnetic resonance upon injection of the conduction electrons; a first electrode electrically coupled with the first magnetic material; and a second electrode electrically coupled with the second magnetic material.
摘要:
There is provided a spin valve transistor that comprises a collector region made of semiconductor, a base region provided on the collector region and including a first ferromagnetic layer whose magnetization direction changes in accordance with a direction of an external magnetic field, a barrier layer provided on the base layer and made of insulator or semiconductor, and an emitter region provided on the barrier layer and including a second ferromagnetic layer whose magnetization direction is fixed.