30 results about "Spin diffusion" patented technology

A method and system for providing a magnetic element that can be used in a magnetic memory is disclosed. The magnetic element includes pinned, spacer, free, and spin barrier layers. The spacer layer is nonmagnetic and resides between the pinned and free layers. The free layer can be switched using spin transfer when a write current is passed through the magnetic element. The free layer resides between the spacer layer and the spin barrier layer. The spin barrier layer is configured to reduce an outer surface contribution to a damping constant of the free layer. In one aspect, the spin barrier layer has a high areal resistance and may substantially eliminate spin pumping induced damping. In another aspect, the magnetic element also includes a spin accumulation layer between the spin barrier and free layers. The spin accumulation layer has a high conductivity, preferably being metallic, and may have a long spin diffusion length.

A method and system for providing a magnetic element that can be used in a magnetic memory is disclosed. The magnetic element includes first pinned, spacer, free, spin barrier, and second pinned layers. The spacer layer is nonmagnetic and resides between the pinned and free layers. The free layer can be switched using spin transfer when a write current is passed through the magnetic element. The free layer resides between the spacer and spin barrier layers. The spin barrier layer is between the free and second pinned layers. The spin barrier layer is configured to reduce an outer surface contribution to the free layer damping constant. In one aspect, the spin barrier layer has a high areal resistance and may substantially eliminate spin pumping induced damping. In another aspect, the magnetic element also includes a spin accumulation layer between the spin barrier and free layers. The spin accumulation layer has a high conductivity and may have a long spin diffusion length.

An ST-MRAM structure, a method for fabricating the ST-MRAM structure and a method for operating an ST-MRAM device that results from the ST-MRAM structure each utilize a spin Hall effect base layer that contacts a magnetic free layer and effects a magnetic moment switching within the magnetic free layer as a result of a lateral switching current within the spin Hall effect base layer. This resulting ST-MRAM device uses an independent sense current and sense voltage through a magnetoresistive stack that includes a pinned layer, a non-magnetic spacer layer and the magnetic free layer which contacts the spin Hall effect base layer. Desirable non-magnetic conductor materials for the spin Hall effect base layer include certain types of tantalum materials and tungsten materials that have a spin diffusion length no greater than about five times the thickness of the spin Hall effect base layer and a spin Hall angle at least about 0.05.

A magnetic sensor reduces thermal fluctuation and realizes high-sensitive signal detection using a spin Hall device of a simple structure configured with only one magnetic layer. The magnetic sensor includes a stacked film in which a nonmagnetic spin Hall layer, a nonmagnetic insulator layer, and a magnetic layer are stacked, an electrode nonmagnetic terminal pair connected to a side surface of the nonmagnetic spin Hall layer, and a unit applying a current in a film thickness direction of the stacked film. A thickness of the nonmagnetic spin Hall layer is thinner than twice a spin diffusion length of a material constituting the nonmagnetic spin Hall layer. A magnetization direction of the magnetic layer magnetized by an external magnetic field is detected due to the polarity of a voltage across both ends of the electrode nonmagnetic terminal pair.

First and second tunnel junctions having a common electrode composed of a nonmagnetic conductor and each of which has a counterelectrode composed of a ferromagnet are spaced apart from each other by a distance that is shorter than a spin diffusion length of the nonmagnetic conductor. The first tunnel junction injects spin from the ferromagnet into the nonmagnetic conductor and the second tunnel junction detects, between the ferromagnetic metal and the nonmagnetic conductor, a voltage that accompanies spin injection of the first tunnel junction. The nonmagnetic conductor may be a semiconductor or semimetal that is lower in carrier density than a metal. The common electrode alternatively may be composed of a superconductor. A spin injection device thus provided can exhibit a large signal voltage with a low current and under low magnetic field and can be miniaturized in device size.

To provide a magnetic reading head that features high resolution and low noise, and that can support a hard disk with terabit-level surface recording density. A current is caused to flow from a pinned layer with its magnetization direction fixed by an antiferro magnetic material, to a non-magnetic thin wire having a portion affected by an external magnetic field and a portion not affected by the external magnetic field, so that spin polarized electrons are accumulated in the non-magnetic thin wire. A distance between voltage terminals of a voltmeter is set to less than the spin diffusion length of the non-magnetic thin wire. A change in the external magnetic field modulates some of the accumulated spin polarized electron, but does not others. Accordingly, an electrical potential difference depending on the external magnetic field is generated between the both end surfaces of the non-magnetic thin wire, and measured with the voltmeter.

A spin accumulation sensor having a three terminal design that allows the free layer to be located at the air bearing surface. A non-magnetic conductive spin transport layer extends from a free layer structure (located at the ABS) to a reference layer structure removed from the ABS. The sensor includes a current or voltage source for applying a current across a reference layer structure. The current or voltage source has a lead that is connected with the non-magnetic spin transport layer and also to electric ground. Circuitry for measuring a signal voltage measures a voltage between a shield that is electrically connected with the free layer structure and the ground. The free layer structure can include a spin diffusion layer that ensures that all spin current is completely dissipated before reaching the lead to the voltage source, thereby preventing shunting of the spin current to the voltage source.

A current-perpendicular-to-the-plane (CPP) magnetoresistive sensor has an antiparallel free (APF) structure as the free layer and a specific direction for the applied bias or sense current. The (APF) structure has a first free ferromagnetic (FL1), a second free ferromagnetic layer (FL2), and an antiparallel (AP) coupling (APC) layer that couples FL1 and FL2 together antiferromagnetically with the result that FL1 and FL2 have substantially antiparallel magnetization directions and rotate together in the presence of a magnetic field. The thicknesses of FL1 and FL2 are chosen to obtain the desired net free layer magnetic moment / area for the sensor, and the thickness of FL1 is preferably chosen to be greater than the spin-diffusion length of the electrons in the FL1 material to maximize the bulk spin-dependent scattering of electrons and thus maximize the sensor signal. The CPP sensor operates specifically with the conventional sense current (opposite the electron current) directed from the pinned ferromagnetic layer to the APF structure, which results in suppression of current-induced noise.

The present disclosure generally relates to a SOT-MRAM cell that has a spin Hall effect layer and a magnetic tunnel junction. The magnetic tunnel junction is disposed at an edge of the spin Hall effect layer. In order to write the cell, current is applied through the spin Hall effect layer to create spin accumulation of z-polarized spins under the free layer due to the spin Hall effect. The spins exert a spin torque on the free layer via spin diffusion. Based upon the design, the SOT-MRAM cell has deterministic switching of the perpendicular free layer with the spin Hall effect layer without application of an external magnetic field.

A current-perpendicular-to-the-plane (CPP) magnetoresistive sensor has an antiparallel free (APF) structure as the free layer and a specific direction for the applied bias or sense current. The (APF) structure has a first free ferromagnetic (FL1), a second free ferromagnetic layer (FL2), and an antiparallel (AP) coupling (APC) layer that couples FL1 and FL2 together antiferromagnetically with the result that FL1 and FL2 have substantially antiparallel magnetization directions and rotate together in the presence of a magnetic field. The thickness of FL1 is preferably greater than the spin-diffusion length of the electrons in the FL1 material. The minimum thickness for FL2 is a thickness resulting in a FL2 magnetic moment equivalent to at least 10 Å Ni80Fe20 and preferably to at least 15 Å Ni80Fe20. The CPP sensor operates specifically with the conventional sense current (opposite the electron current) directed from the pinned ferromagnetic layer to the APF structure, which results in suppression of current-induced noise.

An NMR measurement method adapted for measurements on solid mixture samples starts with irradiating a pulse sequence to the sample in order to measure the longitudinal magnetization relaxation times of nuclei possessing homogeneous longitudinal magnetization relaxation times (step 1). After a lapse of a given period of time t, a high-resolution NMR spectrum is acquired by nullifying spin diffusion across the nuclei (step 2). The steps 1 and 2 are repeated while varying the period of time t. The high-resolution NMR spectra are classified according to value of longitudinal magnetization relaxation time by inverse Laplace transform.

A magnetization reversal device includes a ferromagnetic 12 body which is provided in an interconnection of a non-ferromagnetic dot 11 so that a part or a whole of the ferromagnetic dot is three-dimensionally buried in the interconnection of said non-ferromagnetic dot, and a spin injection source 13 which generates a spin-polarized pure spin current without a flow of charges, and which is provided in the interconnection of the non-ferromagnetic dot 11 to be in contact therewith so that the interconnection of the non-ferromagnetic dot serves as a common electrode, and the pure spin current flows into the ferromagnetic dot 2 through the interconnection of the non-magnetic body by the spin injection source 13 due to a diffusion current, to thereby reverse magnetization of the ferromagnetic dot 12. By injecting the pure spin current, using this planar structure, it is possible to easily carry out the magnetization reversal of the ferromagnetic dot 12 even if it is a thick film ferromagnetic dot without being subjected to limitation of a spin diffusion length.

The invention relates to an optical test method for electron spin diffusion transport kinetics based on a pure phase liquid crystal spatial light modulator, wherein a one-dimensional pure phase liquid crystal spatial light modulator is combined with a time resolution pumping-detecting device, and the principle of an experimental device is indicated in the abstract figures. The one-dimensional pure phase liquid crystal spatial light modulator 7 is arranged in an overlapped area of a pumping light 2 and a detecting light 3, and is used for modulating circular polarization degrees of the cross sections of both the pumping light 2 and the detecting light 3 into the one-dimensional space period distribution. A modulation light field formed like this is imaged onto a sample 9 through an imaging lens 8. The modulated pumping light stimulates an electron spin polarization transient grating in the sample, and the modulated detecting light measures the decay kinetics of the electron spin polarization transient grating. An analytic model for the electron spin diffusion transport kinetics of the circular polarization one-dimensional sinusoidal and square wave type space period modulation light fields is provided. The method disclosed by the invention has the advantages of simple experimental device and operation, capability of testing the spin diffusion transport kinetics with the absorption saturation effect, and high sensitivity.

The invention relates to a perpendicular magnetic anisotropic multi-layered film, which comprises a substrate, a bottom layer, a lower magnetic layer, a middle layer, an upper magnetic layer and a covering layer, wherein at least one of the lower magnetic layer and the upper magnetic layer is a composite magnetic layer which consists of a main layer and a transitional layer, the main layer is made of perpendicular magnetic anisotropic material, and the transitional layer is made of magnetic metal material with spin polarization higher than the spin polarization of the perpendicular magnetic anisotropic material, and is positioned between the main layer and the middle layer. When the middle layer is a barrier layer, the composite magnetic layer also can be made of metal material with a spin diffusion length larger than 3nm. Under the premise of guaranteeing excellent perpendicular magnetic anisotropy, the invention can enhance the magnetoresistance property, reduce mutual magnetostaticreaction and decrease the reverse field or reverse current of a corresponding device. The invention is applicable to giant magnetoresistance devices or tunneling magnetoresistance devices, such as magnetic sensors, magnetic random-access memorys and magnetic logic devices.