Abstract: A magnetic sensor includes a magnetic oscillation element whose oscillation frequency changes depending on the magnitude of an external magnetic field, and an oscillation element provided in the vicinity of the magnetic oscillation element and oscillating at an oscillation frequency close to that of the magnetic oscillation element. The magnetic oscillation element includes a first fixed magnetization layer whose magnetization is fixed, a first magnetization oscillation layer, a first non-magnetic layer provided between the first fixed magnetization layer and the first magnetization oscillation layer, and a pair of electrodes for passing current perpendicularly to the film surfaces of the first fixed magnetization layer, the first magnetization oscillation layer, and the first non-magnetic layer. These two elements are used in combination with the passed current to acquire a high frequency oscillation signal generated from the magnetic oscillation element and the oscillation element.

Abstract: 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; a magnetization free layer whose magnetization direction fluctuates, the magnetization free layer being disposed on the nonmagnetic layer; and a pair of electrodes that applies a current in a direction perpendicular to the film surface of the magnetization fixing layer, the nonmagnetic layer, and the magnetization free layer, wherein 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.

Abstract: 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.

Abstract: A magnetic sensor has a magnetic oscillation element including a first magnetic resonance layer, a second magnetic resonance layer, a nonmagnetic layer sandwiched between the first and second magnetic resonance layers, and a pair of electrodes which supply a current perpendicularly to planes of the first resonance layer, the nonmagnetic layer and the second magnetic resonance layer, and a monitor monitoring a change dependent on an external magnetic field in a change of a high-frequency oscillation voltage generated across the magnetic oscillation element due to precession of magnetization in at least one of the first and second magnetic resonance layers caused by supplying the current.

Abstract: A magnetic oscillating device including a first magnetic resonance layer with a first magnetic resonance frequency f1, a second magnetic resonance layer with a second magnetic resonance frequency f2 higher than the first magnetic resonance frequency f1, a nonmagnetic layer sandwiched between the first magnetic resonance layer and the second magnetic resonance layer, and a pair of electrodes which supplies a current perpendicularly to film planes of the first and second magnetic resonance layers, in which a difference (f2?f1) between the two magnetic resonance frequencies is larger than half a resonance line width of the first magnetic resonance layer, and a ratio of the two magnetic resonance frequencies f2/f1 is 1.6 or less.

Abstract: 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.

Abstract: 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; a base 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.

Abstract: A receiver apparatus includes a preamplifier to amplify an input signal, an equalizer configured to subject an amplified signal to an equalization process, an identification reproducer to reproduce the input signal based on an output signal of the equalizer, and a magnetic oscillator arranged on a pre-stage of the preamplifier to improve a SN ratio of the input signal.

Abstract: The present invention is to be capable of suppressing magnetic white noises as far as possible. A resonant magneto-resistance effect element includes a first magnetic layer whose magnetization direction is substantially parallel to a film plane, a second magnetic film whose magnetization direction is substantially perpendicular to the film plane, and a non-magnetic layer which is provided between the first and second layers.

Abstract: A magnetic memory includes: a spin polarization unit configured to spin-polarize electrons constituting a write current; a hot electron generation unit configured to convert electrons constituting the write current into hot electrons; and a magnetic layer which is subjected to magnetization reversal by the write current that has been spin-polarized by the spin polarization unit and converted into hot electrons by the hot electron generation unit.

Abstract: 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.

Abstract: 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; a base 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.

Abstract: A spin valve transistor, magnetic reproducing head including a spin valve transistor and a magnetic information storage system having the spin valve transistor. The spin valve transistor has a collector, a base formed on the collector, a tunnel barrier layer formed on the base and an emitter formed on the tunnel barrier layer. In one embodiment, the collector may have a first semiconductor layer of first composition and a second semiconductor layer of a different composition epitaxially grown. The base of the first spin valve transistor may be formed on the second semiconductor layer and have a magnetization pinned layer having a magnetization substantially fixed in an applied magnetic field, a nonmagnetic layer and a magnetization free layer having a magnetization free to rotate under the applied magnetic field. The emitter of a spin valve transistor of a second embodiment may include a semiconductor layer containing an oxide of transitional metal and contacting the tunnel barrier layer.

Abstract: 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.

Abstract: A high-frequency oscillation element has a ferromagnetic material which exhibits thermal fluctuation of magnetization and generates spin fluctuations in conduction electrons, a nonmagnetic conductive material which is laminated on the first magnetic material and transfers the conduction electrons, a magnetic material which is laminated on the nonmagnetic conductive material, generates magnetic resonance upon injection of the conduction electrons, and imparts magnetic dipole interaction to magnetization of a neighboring magnetic area by means of magnetic vibration stemming from the magnetic resonance, a first electrode electrically coupled with the first magnetic material, and a second electrode electrically coupled with the second magnetic material.

Abstract: A magnetic memory includes: a spin polarization unit configured to spin-polarize electrons constituting a write current; a hot electron generation unit configured to convert electrons constituting the write current into hot electrons; and a magnetic layer which is subjected to magnetization reversal by the write current that has been spin-polarized by the spin polarization unit and converted into hot electrons by the hot electron generation unit.

Abstract: 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.

Abstract: 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.

Abstract: A spin valve transistor, magnetic reproducing head including a spin valve transistor and-a magnetic information storage system having the spin valve transistor. The spin valve transistor has a collector, a base formed on the collector, a tunnel barrier layer formed on the base and an emitter formed on the tunnel barrier layer. In one embodiment, the collector may have a first semiconductor layer of first composition and a second semiconductor layer of a different composition epitaxially grown. The base of the first spin valve transistor may be formed on the second semiconductor layer and have a magnetization pinned layer having a magnetization substantially fixed in an applied magnetic field, a nonmagnetic layer and a magnetization free layer having a magnetization free to rotate under the applied magnetic field. The emitter of a spin valve transistor of a second embodiment may include a semiconductor layer containing an oxide of transitional metal and contacting the tunnel barrier layer.

Abstract: 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.