Abstract: A nonvolatile storage device includes first and second interconnections and a memory cell between the first and second interconnections. The memory cell includes a storage element, a first switch, and a second switch. The first switch has two terminals and transitions from an off-state to an on-state when a first threshold voltage is applied between its terminals and then voltage between the terminals falls to a first hold voltage. The second switch has two terminals and transitions from an off-state to an on-state when a second threshold voltage is applied between its terminals and then voltage between the terminals falls to a second hold voltage. An off-current of the first switch is less than an off-current of the second switch. The first threshold voltage is greater than the second threshold voltage, which is greater than the first hold voltage, which is greater than or equal to the second hold voltage.

Abstract: A nonvolatile storage device includes first and second interconnections and a memory cell between the first and second interconnections. The memory cell includes a storage element, a first switch, and a second switch. The first switch has two terminals and transitions from an off-state to an on-state when a first threshold voltage is applied between its terminals and then voltage between the terminals falls to a first hold voltage. The second switch has two terminals and transitions from an off-state to an on-state when a second threshold voltage is applied between its terminals and then voltage between the terminals falls to a second hold voltage. An off-current of the first switch is less than an off-current of the second switch. The first threshold voltage is greater than the second threshold voltage, which is greater than the first hold voltage, which is greater than or equal to the second hold voltage.

Abstract: According to one embodiment, a method of manufacturing a magnetic recording head includes forming a microwave oscillator to cover a main pole and a side shield and also to cross at least a part of a side gap between the main pole and the side shield, and lapping the main pole, the side shield and the microwave oscillator in a height direction while monitoring an electric resistance between the main pole and the side shield.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic recording medium, a head including a recording magnetic pole, a spin torque oscillator provided near the recording magnetic pole, and a coil which excites the recording magnetic pole, a first current supply which supplies the coil with a first current corresponding to write data, a detector which detects a first signal corresponding to the write data, and outputs a second signal in accordance with the first signal, and a second power supply which varies, in accordance with the second signal, a second current supplied to the spin torque oscillator.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic recording medium, a head including a recording magnetic pole, a spin torque oscillator provided near the recording magnetic pole, and a coil which excites the recording magnetic pole, a first current supply which supplies the coil with a first current corresponding to write data, a detector which detects a first signal corresponding to the write data, and outputs a second signal in accordance with the first signal, and a second power supply which varies, in accordance with the second signal, a second current supplied to the spin torque oscillator.

Abstract: According to one embodiment, a magnetic recording head includes an air bearing surface, a magnetic core including a main magnetic pole and a write shield arranged to face the main magnetic pole with a write gap, a coil, and a high-frequency oscillator provided between the main magnetic pole and the write shield in the write gap. The magnetic core includes an opposite surface facing a film surface of the high-frequency oscillator, a magnetic layer, and a nonmagnetic layer in which magnetic microparticles are dispersed. The nonmagnetic layer is provided outside the magnetic layer in at least a part of the opposite surface of the magnetic core.

Abstract: According to one embodiment, a magnetic recording head includes an air bearing surface, a magnetic core including a main magnetic pole and a write shield arranged to face the main magnetic pole with a write gap, a coil, and a high-frequency oscillator provided between the main magnetic pole and the write shield in the write gap. The magnetic core includes an opposite surface facing a film surface of the high-frequency oscillator, a magnetic layer, and a nonmagnetic layer in which magnetic microparticles are dispersed. The nonmagnetic layer is provided outside the magnetic layer in at least a part of the opposite surface of the magnetic core.

Abstract: A magnetic head according to an embodiment includes: a 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 method of manufacturing a magnetic recording head includes forming a microwave oscillator to cover a main pole and a side shield and also to cross at least a part of a side gap between the main pole and the side shield, and lapping the main pole, the side shield and the microwave oscillator in a height direction while monitoring an electric resistance between the main pole and the side shield.

Abstract: According to one embodiment, a recording head includes a recoding magnetic pole which applies a recording magnetic field, a write shield which faces the recording magnetic pole across a recording gap, and a spin-torque oscillator provided in the recording gap between the recording magnetic pole and the write shield. The spin-torque oscillator is physically and/or magnetically destroyed and has resistance greater than or equal to a predetermined value.

Abstract: A magnetic head includes a main magnetic pole that applies a recording magnetic field to a recording layer of a recording medium, a recording coil that generates a magnetic field in the main magnetic pole, a microwave oscillator that is disposed in a vicinity of the main magnetic pole, a first wiring electrically connected to recording coil, a second wiring electrically connected to the microwave oscillator, and a low pass filter that is electrically connected to the second wiring.

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: A method for measuring the frequency in a spin torque oscillator having at least a magnetic oscillation layer (MOL), junction layer, and magnetic reference layer (MRL) is disclosed. In a first embodiment, a small in-plane magnetic field is applied to the STO after a DC current is applied to excite the MOL into an oscillation state. The MRL has a perpendicular magnetization that is tilted slightly to give an in-plane magnetization component to serve as a reference layer for measuring the oscillation frequency of the MOL in-plane magnetization component. An AC voltage change is produced in the DC current as a result of variable STO resistance and directly correlates to MOL oscillation frequency. Alternatively, a field having both perpendicular and in-plane components may be applied externally or by forming the STO between two magnetic poles thereby producing an in-plane magnetization reference component in the MRL.

Abstract: A magnetic head includes a plurality of reproducing elements so that the magnetic head can acquire reproduction signals from a plurality of tracks at the same time. The magnetic head includes a first reproducing element, a first magnetic film formed on a first side wall of the first reproducing element with a first side wall insulating film interposed therebetween, a second magnetic film formed on a second side wall of the first reproducing element with a second side wall insulating film interposed therebetween, a second reproducing element electrically isolated from the first reproducing element and formed on the first magnetic film, a third magnetic film formed on the first magnetic film, and a fourth magnetic film formed on the first reproducing element and electrically isolated from the second reproducing element.

Abstract: A recording head of a disk device includes a main magnetic pole, a write shield which faces the main magnetic pole with a write gap interposed therebetween, a coil configured to generate a magnetic field in the main magnetic pole, and a spin torque oscillator which is arranged in the write gap. The spin torque oscillator includes an intermediate layer formed on the main magnetic pole, a field generation layer formed on the intermediate layer, a spin injection layer, and an interface magnetic layer. The field generation layer and the spin injection layer are arranged in parallel to each other in the direction which intersects with the gap length direction of the write gap, and the spin injection layer is electrically connected with the write shield.

Abstract: According to one embodiment, a magnetic recording head includes a main pole, a write shield facing the main pole with a write gap interposed therebetween, a recording coil, and a high-frequency oscillator including an oscillation layer provided within the write gap between an end portion of the main pole and the write shield, and an intermediate layer and a spin-injection layer stacked on the oscillation layer. The oscillation layer, the intermediate layer and the spin-injection layer are stacked in a direction intersecting the gap length direction of the write gap, and at least one of the oscillation layer and the spin-injection layer is electrically connected to one of the main pole and the write shield.

Abstract: According to one embodiment, a magnetic recording head includes a main magnetic pole configured to apply a recording magnetic field to a recording layer of a recording medium, a spin torque oscillator adjacent to the main magnetic pole in a vicinity of a disk-facing surface confronting the recording medium, a recording coil configured to excite the main magnetic pole, a recording current control circuit configured to supply a recording current to the recording coil, a constant current supply circuit configured to supply a constant current to the spin torque oscillator, and an inverted current supply circuit configured to supply an inverted current having a polarity different from the constant current to the spin torque oscillator.

Abstract: A recording head of a disk device includes a main magnetic pole, a write shield which faces the main magnetic pole with a write gap interposed therebetween, a coil configured to generate a magnetic field in the main magnetic pole, and a spin torque oscillator which is arranged in the write gap. The spin torque oscillator includes an intermediate layer formed on the main magnetic pole, a field generation layer formed on the intermediate layer, a spin injection layer, and an interface magnetic layer. The field generation layer and the spin injection layer are arranged in parallel to each other in the direction which intersects with the gap length direction of the write gap, and the spin injection layer is electrically connected with the write shield.

Abstract: According to one embodiment, a magnetic disk apparatus includes a main magnetic pole configured to apply a recording magnetic field to a recording medium, a recording coil configured to magnetize the main magnetic pole, a spin-torque oscillator adjacent to the main magnetic pole, and configured to generate a high frequency magnetic field, a recording current control circuit configured to supply a recording current to the recording coil, a driving current control circuit configured to supply a fixed driving current to the spin-torque oscillator, and an overshoot control circuit configured to control overshoot current of the recording current in proportion to the magnitude of the driving current after the recording current has reversed.

Abstract: According to one embodiment, a magnetic recording head includes a main pole, a write shield facing the main pole with a write gap interposed therebetween, a recording coil, and a high-frequency oscillator including an oscillation layer provided within the write gap between an end portion of the main pole and the write shield, and an intermediate layer and a spin-injection layer stacked on the oscillation layer. The oscillation layer, the intermediate layer and the spin-injection layer are stacked in a direction intersecting the gap length direction of the write gap, and at least one of the oscillation layer and the spin-injection layer is electrically connected to one of the main pole and the write shield.