Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: According to one embodiment, a three-dimensional magnetic recording and reproducing apparatus includes a magnetic head and a magnetic storage medium. The magnetic head includes a spin-torque oscillator including a free layer, a non-magnetic layer and a fixed layer, magnetization of the free layer being rotatable, the non-magnetic layer being laminated on the free layer, the fixed layer being laminated on the non-magnetic layer, a magnetization direction of the fixed layer being fixed. The magnetic storage medium includes first magnetic layers formed of magnetic materials having different resonant frequencies, each of the first magnetic layers being formed of an in-plane magnetization film and having recording tracks.

Abstract: According to one embodiment, a magnetic oscillator includes a layered film and a pair of electrodes. The layered film includes a first ferromagnetic layer, an insulating layer stacked on the first ferromagnetic layer, and a second ferromagnetic layer stacked on the insulating layer. The pair of electrodes is configured to apply a current to the layered film in a direction perpendicular to a film surface of the layered film. Regions having different resistance area products are provided between the first ferromagnetic layer and the second ferromagnetic layer.

Abstract: 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.

Abstract: It is made possible 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.

Abstract: In a spin-torque oscillator, a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer are stacked. A pair of electrodes perpendicularly applies a current onto each plane of the first ferromagnetic layer, the non-magnetic layer and the second ferromagnetic layer. The current induces a precession of a magnetization of at least one of the first ferromagnetic layer and the second ferromagnetic layer. The at least one of the first ferromagnetic layer and the second ferromagnetic layer is formed by an in-plane magnetization film having a uniaxial magnetic anisotropy. A magnetic field generator generates a magnetic field to control a direction of the magnetization so that a non-linearity frequency shift of the precession by the uniaxial magnetic anisotropy cancels a non-linearity frequency shift of the precession by a demagnetizing field on the in-plane magnetization film.

Abstract: 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.

Abstract: 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.

Abstract: In a spin-torque oscillator, a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer are stacked. A pair of electrodes perpendicularly applies a current onto each plane of the first ferromagnetic layer, the non-magnetic layer and the second ferromagnetic layer. The current induces a precession of a magnetization of at least one of the first ferromagnetic layer and the second ferromagnetic layer. The at least one is formed by an in-plane magnetization film having a uniaxial magnetic anisotropy. A magnetic field generator generates a magnetic field to control a direction of the magnetization so that a non-linearity frequency shift of the precession by the uniaxial magnetic anisotropy cancels a non-linearity frequency shift of the precession by a demagnetizing field on the in-plane magnetization film.

Abstract: 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.

Abstract: 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.

Abstract: An apparatus and method for depositing particles having uniform diameters onto a substrate are provided. In the particle deposition apparatus, starting materials in a starting gas are reacted with each other to produce particles which are then deposited onto a substrate. The particle deposition apparatus comprises: a reaction vessel comprising a reaction chamber and a back chamber in its interior, a starting gas supply port in communication with the reaction chamber, an exhaust port in communication with the back chamber, and a holder which is disposed within the back chamber and can hold the substrate; a plasma generator for producing plasma within the reaction chamber; and gas flow control unit configured to discharge a post-reaction gas through the exhaust port while producing the plasma.