238 results about "Bias field" patented technology

A method and system for providing a magnetic memory is disclosed. The method and system include providing a plurality of magnetic storage cells in an array, a plurality of bit lines, and at least one bias structure. Each of the plurality of magnetic storage cells includes at least one magnetic element having an easy axis and being programmable by at least one write current driven through the magnetic element. The plurality of bit lines corresponds to the plurality of magnetic storage cells. The at least one bias structure is magnetically coupled with the at least one magnetic element in each of the plurality of magnetic storage cells. The at least one bias structure provides a bias field in a direction greater than zero degrees and less than one hundred eighty degrees from the easy axis.

Ligand compositions for use in preparing discrete coated nanostructures are provided, as well as the coated nanostructures themselves and devices incorporating same. Methods for post-deposition shell formation on a nanostructure, for reversibly modifying nanostructures, and for manipulating the electronic properties of nanostructures are also provided. The ligands and coated nanostructures of the present invention are particularly useful for close packed nanostructure compositions, which can have improved quantum confinement and / or reduced cross-talk between nanostructures. Ligands of the present invention are also useful for manipulating the electronic properties of nanostructure compositions (e.g., by modulating energy levels, creating internal bias fields, reducing charge transfer or leakage, etc.).

A method and system for providing a magnetic memory device are disclosed. The method and system include providing a magnetic element that includes a data storage layer having at least one easy axis in at least a first direction. The method and system also include providing a hard bias structure surrounding a portion of the magnetic element. The hard bias structure is also configured to provide at least one hard bias field essentially parallel to the at least the first direction or essentially perpendicular to the at least the first direction.

A magnetoresistive read head includes a magnetoresistive sensor and a bias structure adjacent to the magnetoresistive sensor. The bias structure provides a magnetostatic bias field for the magnetoresistive sensor. The bias structure includes an underlayer, a bias layer over the underlayer, and at least one dusting layer directly below at least one of the underlayer or the bias layer.

Ligand compositions for use in preparing discrete coated nanostructures are provided, as well as the coated nanostructures themselves and devices incorporating same. Methods for post-deposition shell formation on a nanostructure, for reversibly modifying nanostructures, and for manipulating the electronic properties of nanostructures are also provided. The ligands and coated nanostructures of the present invention are particularly useful for close packed nanostructure compositions, which can have improved quantum confinement and / or reduced cross-talk between nanostructures. Ligands of the present invention are also useful for manipulating the electronic properties of nanostructure compositions (e.g., by modulating energy levels, creating internal bias fields, reducing charge transfer or leakage, etc.).

In one embodiment of the invention, a semiconductor circuit includes a first group of field effect transistors that are forward body biased and have threshold voltages and a second group of field effect transistors that are not forward body biased and have threshold voltages that are higher than the threshold voltages of the first group of field transistors. In another embodiment of the invention, a semiconductor circuit includes first and second groups of field effect transistors. The circuit includes voltage source circuitry to provide voltage signals to bodies of the first group of field effect transistors to forward body bias the transistors of the first group. When the voltage signals are applied, the transistors of the first group have lower threshold voltages than do the transistors of the second group, except that there may be unintentional variations in threshold voltages due to parameter variations. Other aspects of the invention include forward biased decoupling transistors and a method of testing for leakage.

A method and apparatus for deterministically switching a free layer in a spin orbit torque magnetoresistive random access memory (SOT-MRAM) cell is disclosed herein. In one embodiment, an SOT-MRAM memory cell is provided. The SOT-MRAM memory cell includes a magnetic tunnel junction, a ferromagnetic bias layer, and an antiferromagnetic layer. The magnetic tunnel junction includes a free layer having primarily two bi-stable magnetization directions, a reference layer having a fixed magnetization direction, and an insulating tunnel barrier layer positioned between the free layer and the reference layer. The ferromagnetic bias layer is configured to provide spin orbit torque via anomalous Hall effect and simultaneously configured to provide a magnetic bias field on the free layer to achieve deterministic switching. The antiferromagnetic layer is positioned below the ferromagnetic bias layer and is configured to pin a magnetization direction of the ferromagnetic bias layer in a predetermined direction.

A zero-field paramagnetic resonance magnetometer (ZF-PRM) system and method for quickly and efficiently finding and optimizing the zero-field (ZF) resonance is described. In this system and method a magnetic coil is used to apply a magnetic bias field in the direction of the pump beam to artificially broaden the width and maximize the strength of the ZF resonance. By making the ZF resonance easy to detect, the ZF resonance may be found quickly found without the use of additional components and complex algorithms. Once the ZF resonance is found, a compensating magnetic field can be applied to null the magnetic field in the vicinity of the vapor cell in the ZF-PRM, thereby initializing it for operation.

The invention relates to a three-dimensional brain tumor image segmentation method based on an improved U-Net neural network. The method comprises the following steps: firstly, performing bias field effect removal processing of an N4ITK algorithm on three-dimensional brain tumor MRI image data, and secondly, respectively performing gray normalization preprocessing on each modal image in an original MRI image; building and training an improved U-Net convolutional neural network model; in a training process, inputting the four types of modal data of the patient as four channels of a neural network into an improved U-Net convolutional neural network model for training; the convolutional neural network U-Net being used as a basis, establishing an improved U-Net convolutional neural network model, and the improved U-Net convolutional neural network model comprising an analysis path used for extracting features and a synthesis path used for recovering a target object.

Current-perpendicular-to-plane (CPP) spin valve (SV) and magnetic tunnel junction (MTJ) sensors are provided having an antiparallel (AP)-coupled longitudinal bias stack for instack biasing to stabilize the free layer. A CPP sensor comprises a longitudinal bias stack adjacent to and in contact with a free (sense) layer of the sensor. The bias stack comprises an antiparallel (AP)-pinned layer including FM1 and FM2 layers separated by an antiparallel coupling (APC) layer. The FM1 layer is separated from the free layer of the sensor by a nonmagnetic spacer layer. By choosing the relative thicknesses of the FM1 and FM2 layers, the bias field HB from the AP-pinned layer and the ferromagnetic coupling field HFC between the FM1 layer and the free layer is made additive at the free layer for either positive or negative coupling. By ensuring that the bias field adds to the coupling field, the stability of the free layer by in-stack longitudinal biasing is improved.

A method and system for providing a magnetic element are disclosed. The method and system include providing a magnetic biasing structure having a first pinned layer, a second pinned layer, a spacer layer, and a free layer. The first pinned layer has a first magnetization pinned in a first direction. The second pinned layer has a second magnetization in a second direction that is substantially perpendicular or along the first direction. The spacer layer is nonferromagnetic, resides between the second pinned layer and the free layer, and is configured such that the free layer is substantially free of exchange coupling with the second pinned layer. The free layer has a shape anisotropy with a longitudinal direction substantially in the second direction. The magnetic biasing structure provides a bias field for the free layer along the hard or easy axis. In one aspect, the second pinned layer resides between the first pinned layer and the free layer.

A magnetic random access memory (MRAM) has memory stacks arranged in the X-Y plane on the MRAM substrate, with each memory stack having two memory cells stacked along the Z axis and each memory cell having an associated biasing layer. Each biasing layer reduces the switching field of its associated cell by applying a biasing field along the hard-axis of magnetization of the free layer of its associated cell. The free layers in the two cells in each stack have their in-plane easy axes of magnetization aligned parallel to one another. Each biasing layer has its in-plane magnetization direction oriented perpendicular to the easy axis of magnetization (and thus parallel to the hard axis) of the free layer in its associated cell. The hard-axis biasing fields generated by the two biasing layers are in opposite directions.

A zero-field paramagnetic resonance magnetometer (ZF-PRM) system and method for quickly and efficiently finding and optimizing the zero-field (ZF) resonance is described. In this system and method a magnetic coil is used to apply a magnetic bias field in the direction of the pump beam to artificially broaden the width and maximize the strength of the ZF resonance. By making the ZF resonance easy to detect, the ZF resonance may be found quickly found without the use of additional components and complex algorithms. Once the ZF resonance is found, a compensating magnetic field can be applied to null the magnetic field in the vicinity of the vapor cell in the ZF-PRM, thereby initializing it for operation.

A magnetic random access memory (MRAM) has memory stacks arranged in the X-Y plane on the MRAM substrate, with each memory stack having two memory cells stacked along the Z axis and each memory cell having an associated biasing layer. Each biasing layer reduces the switching field of its associated cell by applying a biasing field along the hard-axis of magnetization of the free layer of its associated cell. The free layers in the two cells in each stack have their in-plane easy axes of magnetization aligned parallel to one another. Each biasing layer has its in-plane magnetization direction oriented perpendicular to the easy axis of magnetization (and thus parallel to the hard axis) of the free layer in its associated cell. The hard-axis biasing fields generated by the two biasing layers are in opposite directions.

An AMR gear tooth rotation sensor and a method for utilizing it are disclosed. These facilitate easy manufacture of the device without sacrificing either high sensitivity or high signal output. This is achieved by forming individual sensing elements out of AMR stripes and then connecting four such sensing elements as a Wheatstone bridge. The latter is attached to a permanent magnet that provides a bias field whose value rises and falls as wheel teeth and valleys (respectively) move past the rotation sensor.

A MR sensor is disclosed that has a free layer (FL) with perpendicular magnetic anisotropy (PMA) which eliminates the need for an adjacent hard bias structure to stabilize free layer magnetization and minimizes shield-FL interactions. In a TMR embodiment, a seed layer, free layer, junction layer, reference layer, and pinning layer are sequentially formed on a bottom shield. After patterning, a conformal insulation layer is formed along the sensor sidewall. Thereafter, a top shield is formed on the insulation layer and includes side shields that are separated from the FL by a narrow read gap. The sensor is scalable to widths <50 nm when PMA is greater than the FL self-demag field. Effective bias field is rather insensitive to sensor aspect ratio which makes tall stripe and narrow width sensors a viable approach for high RA TMR configurations. Side shields may be extended below the seed layer plane.

The present invention has an object to provide a nuclear magnetic resonance imaging apparatus or the like that avoids a region with zero sensitivity of an optical magnetometer and allows imaging by strong magnetic resonance when a common magnetic field is used as a bias field of an optical magnetometer and as a magnetostatic field to be applied to a sample. When a direction of a magnetostatic field application unit applying a magnetostatic field to a sample is a z direction, alkali metal cells of a plurality of scalar magnetometers are arranged so as not to overlap a region to be imaged in a z direction, and so as not to intersect the region to be imaged in an in-plane direction perpendicular to the z direction.

A read head, particularly suitable for a magnetic disc storage system, includes a read sensor having an air-bearing surface and an opposing top surface. The read head also includes a permanent magnet positioned adjacent the top surface of the read sensor for generating a magnetic bias field in the read sensor. The permanent magnet has a magnetization in a direction other than normal to the air-bearing surface of the read sensor.

A current-perpendicular-to-the plane magnetoresistive sensor with a self-pinned in-stack longitudinal bias structure is provided comprising a ferromagnetic bias layer formed of material having a negative magnetostriction coefficient and a spacer layer for antiparallel coupling to a free layer. The negative magnetostriction of the bias layer interacts with the lapping-induced stress anisotropy of the sensor stack to provide strong pinning of the magnetization of the bias layer in a direction parallel to the ABS and antiparallel to the direction of the magnetization of the free layer. Magnetostatic coupling of the bias layer magnetization with the free layer provides a longitudinal bias field to stabilize the free layer magnetization.

A magnetoelectric magnetic field sensor has one or more laminated magnetostrictive layers and piezoelectric layers. The magnetostrictive layers are magnetized by a bias magnetic field in a longitudinal, in-plane direction. The piezoelectric layers can be poled in the longitudinal direction or perpendicular direction. The longitudinal magnetization of the magnetostrictive layers provides greatly increased sensitivity at lower bias fields compared to other magnetoelectric sensors. Perpendicular poling of the piezoelectric layers tends to provide higher sensitivity at lower detection frequency (e.g. less than 1 Hz). Longitudinal poling tends to provide higher sensitivity at high detection frequency (e.g. above 10 Hz). Also included are embodiments having relative thicknesses for the magnetostrictive layers that are optimized for sensitivity. Equations are provided for calculating the best relative thickness for the magnetostrictive layer for maximum sensitivity.

A magnetostrictive element for use in a magneto-mechanical marker has a resonant frequency characteristic that is at a minimum at a bias field level corresponding to the operating point of the magnetomechanical marker. The magnetostrictive element has a magnetomechanical coupling factor k in the range 0.28 to 0.4 at the operating point. The magnetostrictive element is formed by applying cross-field annealing to an iron-rich amorphous metal alloy ribbon (45 to 82 percent iron) which includes a total of from 2 to 17 percent of one or more of Mn, Mo, Nb, Cr, Hf, Zr, Ta, V. Cobalt, nickel, boron, silicon and / or carbon may also be included. The metal alloy may include one early transition element selected from the group consisting of Zr, Hf and Ta, and also a second early transition element selected from the group consisting of Mn, Mo, Nb, Cr, and V.

The present invention has an object to provide a nuclear magnetic resonance imaging apparatus or the like that avoids a region with zero sensitivity of an optical magnetometer and allows imaging by strong magnetic resonance when a common magnetic field is used as a bias field of an optical magnetometer and as a magnetostatic field to be applied to a sample. When a direction of a magnetostatic field application unit applying a magnetostatic field to a sample is a z direction, alkali metal cell of a scalar magnetometer is arranged so as not to overlap a region to be imaged in a z direction, and so as not to intersect the region to be imaged in an in-plane direction perpendicular to the z direction.

A magnetic scissor type magnetic read head having magnetic side shielding for reduced effective track width and having side biasing for improved stability. The read head includes first and magnetic side shields that each include first and second magnetic layers and an anti-parallel exchange coupling layer sandwiched there-between. The magnetic layers of the side shields are anti-parallel coupled with one another such that one of the magnetic layers has its magnetization oriented in a first direction parallel with the air bearing surface and the second magnetic layer has its magnetization oriented in a second direction that is opposite to the first direction and also parallel with the air bearing surface. These magnetizations of the first and second magnetic layers provide a bias field that stabilizes the magnetization of the free magnetic layers of the sensor stack to prevent flipping of the magnetizations of these layers.

A method for manufacturing a magnetic sensor that result in improved magnetic bias field to the sensor, improved shield to hard bias spacing and a flatter top shield profile. The method includes a multi-angled deposition of the hard bias structure. After forming the sensor stack a first hard bias layer is deposited at an angle of about 70 degrees relative to horizontal. This is a conformal deposition. Then, a second deposition is performed at an angle of about 90 degrees relative to horizontal. This is a notching deposition, that results in notches being formed adjacent to the sensor stack. Then, a hard bias capping layer is deposited at an angle of about 55 degrees relative to horizontal. This is a leveling deposition that further flattens the surface on which the top shield can be electroplated.

The present invention relates to a magnetoresistive sensor for measuring a magnetic field. A calculation of the sensitivity to external magnetic fields is provided, and it is shown to be related to the shape anisotropy of the magnetoresistive sensing elements. Moreover, it is shown that sensitivity may be made highest when the shape of the magnetoresistive element is long parallel to the sensing axis, and a magnetic bias field strong enough to saturate the magnetoresistive element's magnetization, Hcross, is applied perpendicular to the sensing axis. A monolithic permanent magnet is provided to generate the Hcross and it may be applied at an angle in order to counteract non-ideal fields along the sense axis direction. The high sensitivity magnetoresistive element can be used in many electrical form-factors. Six exemplary bridge configurations are described herein.

A superconducting short circuit current limiter (40a) for an alternating current system includes AC reactors having superconducting direct current bias windings (4a, 4b) that at normal conditions maintain the reactor's cores in saturated state. There are at least two AC coils (3a, 3b) for each phase operating at opposite half periods or at both half periods. The reactor may also have an additional feedback coil (42a, 42b) that at least partly compensates for the bias field of the superconducting coil at fault conditions enhancing a limiting capacity of the reactor. The reactor's core can be configured for decreasing its dimensions and mass as compared with known devices and for decreasing core losses. High voltage / high current devices include several standard modules connected in series or / and in parallel. A positional relationship of the modules is defined for decreasing necessary numbers of Amp?re-turns of superconducting and non-superconducting coils.

A current-perpendicular-to-the plane magnetoresistive sensor with a self-pinned in-stack longitudinal bias structure is provided comprising a ferromagnetic bias layer formed of material having a negative magnetostriction coefficient and a spacer layer for antiparallel coupling to a free layer. The negative magnetostriction of the bias layer interacts with the lapping-induced stress anisotropy of the sensor stack to provide strong pinning of the magnetization of the bias layer in a direction parallel to the ABS and antiparallel to the direction of the magnetization of the free layer. Magnetostatic coupling of the bias layer magnetization with the free layer provides a longitudinal bias field to stabilize the free layer magnetization.

The invention discloses a liquid crystal phase shift unit and a phased antenna composed of the same. The liquid crystal phase shift unit is characterized in that a sandwich layer is formed by an upper-layer dielectric substrate and a lower-layer dielectric substrate which are arranged in parallel, nematic liquid crystal is enclosed in the sandwich layer to form a liquid crystal layer, metal micro-strip structures are formed on the surface of the upper-layer dielectric substrate and the surface of the lower-layer dielectric substrate, bias voltage is applied by means of the metal micro-strip structures, bias field is formed in the liquid crystal layer to enable the arrangement direction of liquid crystal molecules in the liquid crystal layer to be changed, and then the dielectric constant of the liquid crystal layer is changed and the phase position of reflected waves is changed; in an array formed by the liquid crystal phase shift unit, needed phase distribution is realized by applying different voltages to different units, so that corresponding wave beam directions are obtained or wavefront beamforming is achieved. Phase shift characteristics are changed with an electrical control method, working at the frequency band of 100-1000 GHz can be achieved, machining is easy, miniaturization is achieved, and cost is low.