Abstract: According to one embodiment, a magnetic head includes a reproducing portion. The reproducing portion includes first to fourth magnetic portions and a stacked body. The third magnetic portion is provided between the first and second magnetic portions. The fourth magnetic portion is provided between the first and second magnetic portions. A second direction from the third magnetic portion toward the fourth magnetic portion crosses a first direction from the first magnetic portion toward the second magnetic portion. The stacked body is provided between the first and second magnetic portions in the first direction and between the third and fourth magnetic portions in the second direction. The stacked body includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the second magnetic portion in the first direction, and an intermediate layer provided between the first and second magnetic layers in the first direction.

Abstract: According to one embodiment, a magnetic head includes a magnetic pole, a first shield, a magnetic layer, a first conductive layer, and a second conductive layer. The magnetic layer is provided between the magnetic pole and the first shield. The first conductive layer includes at least one of Cu, Ag, Au, Al and Cr, and is provided between the magnetic pole and the first shield. A direction from the first conductive layer toward the magnetic layer crosses a first direction from the magnetic pole toward the first shield. A second conductive layer includes at least one of Ta, Pt, W, Ru, Mo, Ir, Rh, and Pd and is provided at one of a first position or a second position. The first position is between the first conductive layer and the first shield. The second position is between the magnetic pole and the first conductive layer.

Abstract: According to one embodiment, a magnetic head includes a reproducing portion. The reproducing portion includes first to fourth magnetic portions and a stacked body. The third magnetic portion is provided between the first and second magnetic portions. The fourth magnetic portion is provided between the first and second magnetic portions. A second direction from the third magnetic portion toward the fourth magnetic portion crosses a first direction from the first magnetic portion toward the second to magnetic portion. The stacked body is provided between the first and second magnetic portions in the first direction and between the third and fourth magnetic portions in the second direction. The stacked body includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the second magnetic portion in the first direction, and an intermediate layer provided between the first and second magnetic layers in the first direction.

Abstract: According to one embodiment, an oscillator includes a first element. The first element includes first and second magnetic layers, and a first nonmagnetic layer. The first magnetic layer includes first and second magnetic films, and a first nonmagnetic film. The second magnetic film is provided between the second magnetic layer and the first magnetic film. The first nonmagnetic layer is provided between the second magnetic film and the second magnetic layer. An orientation of a first magnetization of the first magnetic film has a reverse component of an orientation of a second magnetization of the second magnetic film. A first magnetic field is applied to the first element. The first element is in a first state when a first current flows in the first element. An electrical resistance of the first element in the first state includes first and second electrical resistances repeating alternately.

Abstract: According to one embodiment, a magnetic head includes a reproducing portion. The reproducing portion includes first to fourth magnetic portions and a stacked body. The third magnetic portion is provided between the first and second magnetic portions. The fourth magnetic portion is provided between the first and second magnetic portions. A second direction from the third magnetic portion toward the fourth magnetic portion crosses a first direction from the first magnetic portion toward the second magnetic portion. The stacked body is provided between the first and second magnetic portions in the first direction and between the third and fourth magnetic portions in the second direction. The stacked body includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the second magnetic portion in the first direction, and an intermediate layer provided between the first and second magnetic layers in the first direction.

Abstract: According to one embodiment, a magnetic head includes a first magnetic layer, a second magnetic layer, an intermediate layer, a magnetic pole, a first terminal, and a second terminal. The second magnetic layer is separated from the first magnetic layer in a first direction. The intermediate layer is provided between the first magnetic layer and the second magnetic layer. A second direction from the first magnetic layer toward the magnetic pole crosses the first direction. The first terminal is electrically connected to the intermediate layer. The second terminal is electrically connected to the second magnetic layer.

Abstract: According to one embodiment, a magnetic head includes a reproducing portion. The reproducing portion includes first to fourth magnetic portions and a stacked body. The third magnetic portion is provided between the first and second magnetic portions. The fourth magnetic portion is provided between the first and second magnetic portions. A second direction from the third magnetic portion toward the fourth magnetic portion crosses a first direction from the first magnetic portion toward the second magnetic portion. The stacked body is provided between the first and second magnetic portions in the first direction and between the third and fourth magnetic portions in the second direction. The stacked body includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the second magnetic portion in the first direction, and an intermediate layer provided between the first and second magnetic layers in the first direction.

Abstract: According to one embodiment, a magnetic recording medium includes a first layer and a second layer. The first layer includes a first magnetic region, a second magnetic region, and a nonmagnetic region provided between the first and second magnetic regions. A direction from the second magnetic region toward the first magnetic region is along a first direction. The second layer includes third, fourth, and fifth magnetic regions. At least a portion of the fifth magnetic region is provided between the third and fourth magnetic regions. The third magnetic region overlaps the first magnetic region in a second direction crossing the first direction. The fourth magnetic region overlaps the second magnetic region in the second direction. The fifth magnetic region overlaps the nonmagnetic region in the second direction. An easy magnetization axis of each of the first to fifth magnetic regions is aligned with the second direction.

Abstract: According to one embodiment, an oscillator includes a first element. The first element includes first and second magnetic layers, and a first nonmagnetic layer. The first magnetic layer includes first and second magnetic films, and a first nonmagnetic film. The second magnetic film is provided between the second magnetic layer and the first magnetic film. The first nonmagnetic layer is provided between the second magnetic film and the second magnetic layer. An orientation of a first magnetization of the first magnetic film has a reverse component of an orientation of a second magnetization of the second magnetic film. A first magnetic field is applied to the first element. The first element is in a first state when a first current flows in the first element An electrical resistance of the first element in the first state includes first and second electrical resistances repeating alternately.

Abstract: According to one embodiment, a magnetic recording and reproducing device includes a magnetic recording medium, a magnetic head, and a controller. The controller implements a first operation and a second operation. The first operation is implemented in a first information recording interval including a first recording interval and a first non-recording interval. The second operation is implemented in a second information recording interval including a second recording interval and a second non-recording interval. The first operation includes in the first recording interval, generating a first signal magnetic field from the magnetic head, and in the first non-recording interval, generating a first non-signal magnetic field from the magnetic head. The second operation includes in the second recording interval, generating a second signal magnetic field from the magnetic head, and in the second non-recording interval, generating a second non-signal magnetic field from the magnetic head.

Abstract: According to one embodiment, a microwave sensor includes a first stacked body and a first controller. The first stacked body includes a first magnetic layer, a second magnetic layer, and a first nonmagnetic layer. The first nonmagnetic layer is provided between the first magnetic layer and the second magnetic layer. The first controller is electrically connected to the first magnetic layer and the second magnetic layer. The first controller is configured to supply a current to the first stacked body and is configured to sense a value corresponding to a first electrical resistance between the first magnetic layer and the second magnetic layer. A second magnetization of the second magnetic layer is aligned with a first direction from the first magnetic layer toward the second magnetic layer. The value corresponding to the first electrical resistance changes according to a microwave.

Abstract: According to one embodiment, a magnetic head includes a first magnetic layer, a second magnetic layer, an intermediate layer, a magnetic pole, a first terminal, and a second terminal. The second magnetic layer is separated from the first magnetic layer in a first direction. The intermediate layer is provided between the first magnetic layer and the second magnetic layer. A second direction from the first magnetic layer toward the magnetic pole crosses the first direction. The first terminal is electrically connected to the intermediate layer. The second terminal is electrically connected to the second magnetic layer.

Abstract: According to an embodiment, a computing apparatus includes spin torque oscillators, an interaction unit, a variable direct-current supply device, and a measuring unit. The interaction unit controls an interaction between the spin torque oscillators. The variable direct-current supply device supplies a current to induce oscillations of the spin torque oscillators. The measuring unit measures AC signals obtained from the spin torque oscillators.

Abstract: A magnetic recording and reproducing apparatus for recording and reproducing bit information comprising a magnetic head having a spin torque oscillator configured to readout bit information which is recorded on a magnetic recording medium, a detector configured to detect amplitude of a first signal, the first signal which is to reproduce the bit information, and a controller configured to control the magnetic head so as to read the bit information recorded on the magnetic recording medium when the amplitude of the first signal detected by the detector is smaller than a predetermined value.

Abstract: A magnetic recording and reproducing apparatus for recording and reproducing bit information comprising a magnetic head having a spin torque oscillator configured to readout bit information which is recorded on a magnetic recording medium, a detector configured to detect amplitude of a first signal, the first signal which is to reproduce the bit information, and a controller configured to control the magnetic head so as to read the bit information recorded on the magnetic recording medium when the amplitude of the first signal detected by the detector is smaller than a predetermined value.

Abstract: According to an embodiment, a computing apparatus includes spin torque oscillators, an interaction unit, a variable direct-current supply device, and a measuring unit. The interaction unit controls an interaction between the spin torque oscillators. The variable direct-current supply device supplies a current to induce oscillations of the spin torque oscillators. The measuring unit measures AC signals obtained from the spin torque oscillators.

Abstract: According to one embodiment, a magnetic recording and reproducing device includes a magnetic recording medium, a magnetic head, and a controller. The controller implements a first operation and a second operation. The first operation is implemented in a first information recording interval including a first recording interval and a first non-recording interval. The second operation is implemented in a second information recording interval including a second recording interval and a second non-recording interval. The first operation includes in the first recording interval, generating a first signal magnetic field from the magnetic head, and in the first non-recording interval, generating a first non-signal magnetic field from the magnetic head. The second operation includes in the second recording interval, generating a second signal magnetic field from the magnetic head, and in the second non-recording interval, generating a second non-signal magnetic field from the magnetic head.

Abstract: According to one embodiment, a magnetic recording apparatus includes a spin-torque oscillator, a recording unit, and a controller. The spin-torque oscillator includes an oscillation layer. The recording unit includes at least one recording layer. Magnetization reversal in each recording layer is performed by excitation of cooperative dynamics between magnetization of the oscillation layer and magnetization of the recording layer. The controller controls precession of the magnetization of the oscillation layer, which is induced by application of an electric current to the spin-torque oscillator.

Abstract: According to one embodiment, a magnetic recording medium includes a first magnetic layer and a second magnetic layer. An easy magnetization axis of the first magnetic layer is aligned with a first direction. The first direction is from the first magnetic layer toward the second magnetic layer. The second magnetic layer has magnetic anisotropy in a plane perpendicular to the first direction. A second magnetization of the second magnetic layer is reverse orientation of a first magnetization of the first magnetic layer.

Abstract: According to an embodiment, a magnetic recording head includes a main magnetic pole and a spin torque oscillator. The spin torque oscillator includes a first perpendicular free layer, a second perpendicular free layer, and a first spacer layer, each of the first perpendicular free layer and the second perpendicular free layer including a magnetic anisotropy axis in a direction perpendicular to a film plane of the spin torque oscillator. An effective perpendicular magnetic anisotropy magnetic field of the first perpendicular free layer is smaller than an effective perpendicular magnetic anisotropy magnetic field of the second perpendicular free layer, and a current is applied from the first perpendicular free layer side to the second perpendicular free layer side.