Abstract: Disclosed in the embodiments of the present invention are a laser writing apparatus and method for programming magnetoresistive devices. The apparatus comprises: a substrate, a magnetoresistive sensor and a thermal control layer which are sequentially arranged in a stacked manner. A non-magnetic insulating layer for electrical isolation is provided between the magnetoresistive sensor and the thermal control layer. The magnetoresistive sensor is composed of a magnetoresistive sensing unit which is a multilayer thin-film stacked structure containing an anti-ferromagnetic layer.

Abstract: A magnetic sensor packaging structure with a hysteresis coil comprising a substrate, a sensor chip, a spiral hysteresis coil on the substrate, and wire bonding pads. The sensor bridge arms are composed of magnetoresistive sensing elements. The sensor bridge arms are deposited on the sensor chip, and the sensor bridge arms are electrically interconnected to form a magnetoresistive sensor bridge that is located on the hysteresis coil. The magnetic field generated by the spiral hysteresis coil is collinear with a sensitive axis of the sensor bridge. The magnetoresistive sensor bridge is located on the substrate and encapsulated. By placing the spiral hysteresis coil on the substrate, it is capable of supporting larger currents with smaller resistance value. This allows the sensor hysteresis to be effectively eliminated. In addition, the packaging structure manufacturing process is simple and cost effective.

Abstract: A type of rotating disk magnetic field probe (1) comprising: a non-magnetic rotating disk (2), 4N first soft ferromagnetic sectors (3), M second soft ferromagnetic sectors (4), a reference signal generator, an X-axis magnetoresistive sensor (7, 8), a Y-axis magnetoresistive sensor (5,6), and a Z-axis magnetoresistive sensor (9). Both the first soft ferromagnetic sectors (3) and the second soft ferromagnetic sector (4) are located on the non-magnetic rotating disk (2). In operation, the non-magnetic rotating disk (2) rotates about a Z-axis at a frequency f. An external magnetic field is modulated by the first soft ferromagnetic sector (3) into an X-axis magnetic field sensed component and a Y-axis magnetic field sensed component having a frequency of 4N×f, and is modulated by the second soft ferromagnetic field sectors into a Z-axis magnetic field sensed component having a frequency of M×f.

Abstract: A magnetic sensor packaging structure with a hysteresis coil comprising a substrate, a sensor chip, a spiral hysteresis coil on the substrate, and wire bonding pads. The sensor bridge arms are composed of magnetoresistive sensing elements. The sensor bridge arms are deposited on the sensor chip, and the sensor bridge arms are electrically interconnected to form a magnetoresistive sensor bridge that is located on the hysteresis coil. The magnetic field generated by the spiral hysteresis coil is collinear with a sensitive axis of the sensor bridge. The magnetoresistive sensor bridge is located on the substrate and encapsulated. By placing the spiral hysteresis coil on the substrate, it is capable of supporting larger currents with smaller resistance value. This allows the sensor hysteresis to be effectively eliminated. In addition, the packaging structure manufacturing process is simple and cost effective.

Abstract: A magnetoresistive magnetic field probe with rotating electromechanical modulator (1) comprises: a bulk cylindrical base (11), wherein the bulk cylindrical base (11) has a cavity structure, and a center axis of the bulk cylindrical base (11) overlaps with a z-axis of a cylindrical coordinate system; a first magnetic tile (12) and a second magnetic tile (13) attached to an outer side wall of the bulk cylindrical base (11); and a magnetoresistive sensor (14) and a reference signal generator (15) located on the center axis of the bulk cylindrical base (11). During operation, the bulk cylindrical base (11) rotates about the z-axis at a frequency f, and the first magnetic tile (12) and the second magnetic tile (13) modulate an external magnetic field into a sensed magnetic field having a frequency 2f, and a measurement signal having a frequency 2f is output via the magnetoresistive sensor (14). The reference signal generator (15) outputs a reference signal having a frequency 2f.

Abstract: An automatic magnetic flow recording device, comprises a multitude of coaxially disposed hard magnetic rotating wheels wherein the hard magnetic rotating wheels are circular, and rotate with respect to each other by a predetermined transmission ratio. Each hard magnetic rotating wheel has at least one corresponding biaxial magnetoresistive angle sensor. The biaxial magnetoresistive angle sensors measure the angular positions of the hard magnetic rotating wheels within the range of 0-360 degrees. The biaxial magnetoresistive angle sensors comprise two single-axis linear magnetoresistive sensors, wherein the single-axis linear magnetoresistive sensors are an X-axis magnetoresistive sensor or a Z-axis magnetoresistive sensor. The X-axis magnetoresistive sensor of the hard magnetic rotating wheel measures a magnetic field component parallel to the tangent of the circumference of the hard magnetic rotating wheel.

Abstract: A gain-controllable magnetoresistive analog amplifier comprises a substrate located in an X-Y plane, an output signal magnetoresistive sensor located on the substrate, and an input signal coil and a gain adjustment coil. The input signal coil and the gain adjustment coil are respectively located on two side surfaces of the output signal magnetoresistive sensor. The gain adjustment coil is used to input a gain signal by the generation of a gain magnetic field, in order to set the gain the magnetic field is applied along a magnetization direction of a free layer of the output signal magnetoresistive sensor, thereby adjusting the slope of the input resistance-magnetic field transfer curve of the output signal magnetoresistive sensor.

Abstract: A magnetoresistive Z-axis gradient sensor chip, which is used to detect the gradient in the XY plane of a Z-axis magnetic field component generated by a magnetic medium; the sensor chip comprises a Si substrate, a collection of two or two groups of flux guide devices separated a distance Lg and an arrangement of electrically interconnected magnetoresistive sensor units. The magnetoresistive sensor units are located on the Si substrate and located above or below the edge of the flux guide devices as well; the flux guide devices convert the component of the Z-axis magnetic field into the direction parallel to the surface of the Si substrate along the sensing axis direction of the magnetoresistive sensing units. The magnetoresistive sensor units are electrically interconnected into a half bridge or a full bridge gradiometer arrangement, wherein the opposite bridge arms are separated by distance Lg. This sensor chip can be utilized with a PCB or in combination with a PCB plus back-bias magnet with casing.

Abstract: A single-chip two-axis magnetoresistive angle sensor comprises a substrate located in an X-Y plane, a push-pull X-axis magnetoresistive angle sensor and a push-pull Y-axis magnetoresistive angle sensor located on the substrate. The push-pull X-axis magnetoresistive angle sensor comprises an X push arm and an X pull arm. The push-pull Y-axis magnetoresistive angle sensor comprises a Y push arm and a Y pull arm. Each of the X push, X pull, Y push arm, and Y pull arms comprises at least one magnetoresistive angle sensing array unit. The magnetic field sensing directions of the magnetoresistive angle sensing array units of the X push, X pull, Y push, and Y pull arms are along +X, ?X, +Y and ?Y directions respectively. Each magnetoresistive sensing unit comprises a TMR or GMR spin-valve having the same magnetic multi-layer film structure.

Abstract: A hydrogen gas sensor utilizing electrically isolated tunneling magnetoresistive stress sensing elements is disclosed. The hydrogen gas sensor comprises: a deformable substrate, a magnetoresistive bridge stress sensor located on the deformable substrate, an electrical isolation layer covering the magnetoresistive bridge stress sensor, a magnetic shielding layer located on the electrical isolation layer, and a hydrogen sensing layer located above the deformable substrate. The hydrogen sensing layer is located in a plane perpendicular to the deformation of the substrate covering the electrical isolation layer. The hydrogen sensing layer is used for absorbing or desorbing hydrogen gas to generate expansion or contraction deformation and cause a stress change of the deformable substrate. The magnetoresistive bridge stress sensor is used for measuring a hydrogen gas concentration utilizing the stress change of the deformable substrate. It results in a hydrogen gas sensor with improved performance.

Abstract: A hydrogen gas sensor utilizing electrically isolated tunneling magnetoresistive sensing elements is provided. The hydrogen gas sensor comprises: a substrate in an X-Y plane, tunneling magnetoresistive sensors located on the substrate, and a hydrogen sensing layer located on the tunnel magnetoresistive sensors. The hydrogen sensing layer and the tunneling magnetoresistive sensor are electrically isolated from each other. The hydrogen sensing layer includes a multi-layer thin film structure formed from palladium layers and ferromagnetic layers, wherein the palladium layers are used for absorbing hydrogen in the air that causes a change in the orientation angle of a magnetic anisotropy field in each of the ferromagnetic layers in the X-Z plane into an X-axis direction. The tunnel magnetoresistive sensors are used for detecting a magnetic field signal of the hydrogen sensing layer, wherein the magnetic signal determines the hydrogen gas concentration. This hydrogen gas sensor ensures measurement safety.

Abstract: A magnetoresistive hydrogen sensor and sensing method thereof, wherein the hydrogen sensor comprises a substrate located in an X-Y plane, magnetoresistive sensing units and magnetoresistive reference units located on the substrate. The magnetoresistive sensing units are electrically connected to form a sensing arm, and the magnetoresistive reference units are electrically connected to form a reference arm. The sensing arm and the reference arm are electrically interconnected to form a referenced bridge structure. The magnetoresistive sensing units and the magnetoresistive reference units may be AMR units having the same magnetic multilayer thin film structure, GMR spin valves, or GMR multilayer film stacks having the same magnetic multilayer thin film structure. The magnetoresistive sensing units and the magnetoresistive reference units are respectively covered with a Pd layer, and a passivating insulation layer is deposited over the Pd layer of the magnetoresistive reference units.

Abstract: Disclosed is a digital liquid level sensor based on a magnetoresistive sensor cross-point array, including: a plurality of TMR magnetic sensor chips; a microcontroller, a row decoder, and a column decoder, wherein the microcontroller is electrically connected to the row decoder and the column decoder, the TMR magnetic sensor chips include a plurality of MTJ elements, diodes are connected between each row of MTJ elements and a row lead or a column lead, the TMR magnetic sensor chips are addressed by means of data decoded by the row decoder and the column decoder and on the basis of the equation Address=m+[M×(n?1)], Address representing an address value, and m representing the value of a current row, and the microcontroller is used for scanning addresses of the TMR magnetic sensor chips for the address of an MTJ element in the highest active state, converting the address value into a liquid level value in a linear proportional relationship therewith, and transmitting the liquid level value to an output interfac

Abstract: A resettable bipolar switch sensor is disclosed which comprises a bipolar magnetic hysteresis switch sensor, a reset coil, an ASIC switch circuit and a power reset circuit. The bipolar magnetic hysteresis switch sensor comprises a substrate and a magnetoresistive sensing arm located on the substrate. The magnetoresistive sensing arm is of a two-port structure composed of one or more magnetoresistive sensing unit strings arranged in series, parallel, or series-parallel. The magnetization direction of a free layer of a TMR magnetoresistive sensing unit is determined by an anisotropy field Hk, and together with the magnetization direction of a reference layer and the applied magnetic field, it can orient in an N or S direction. The reset coil is located between the substrate along with the magnetoresistive sensing unit, or it is located on a lead frame below the substrate. The direction of the reset magnetic field is either N or S.

Abstract: 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.

Abstract: A modulated magnetoresistive sensor consists of a substrate located on a substrate in an XY plane, magnetoresistive sensing elements, a modulator, electrical connectors, an electrical insulating layer, and bonding pads. The sensing direction of the magnetoresistive sensing elements is parallel to the X axis. The magnetoresistive sensing elements are connected in series into a magnetoresistive sensing element string. The modulator is comprised of multiple elongated modulating assemblies. The elongated modulating assemblies consist of three layers—FM1 layer, NM layer, and FM2 layer. The ends of the elongated modulating assemblies are electrically connected to form a serpentine current path. The electrical insulating layer is set between the elongated modulating assemblies and the magnetoresistive sensing elements to separate the elongated modulating assemblies from the magnetoresistive sensing elements.

Abstract: A three-axis upstream-modulated low-noise magnetoresistive sensor comprises an X-axis magnetoresistive sensor, a Y-axis magnetoresistive sensor, and a Z-axis magnetoresistive sensor, wherein the X, Y, and Z-axis magnetoresistive sensors respectively comprise X, Y, and Z-axis magnetoresistive sensing unit arrays, X, Y, and Z-axis soft ferromagnetic flux concentrator arrays, and X, Y, and Z-axis modulator wire arrays. The X, Y, and Z-axis magnetoresistive sensing unit arrays are electrically interconnected into X, Y, and Z-axis magnetoresistive sensing bridges respectively. The X, Y, and Z-axis modulator wire arrays are electrically interconnected into individual two-port X, Y, and Z-axis excitation coils. In order to measure external magnetic fields, the two-port X, Y, and Z-axis excitation coils are separately supplied with high-frequency alternating current at a frequency f, from a current supply.

Abstract: A magnetoresistive hydrogen sensor and sensing method thereof, wherein the hydrogen sensor comprises a substrate located in an X-Y plane, magnetoresistive sensing units and magnetoresistive reference units located on the substrate. The magnetoresistive sensing units are electrically connected to form a sensing arm, and the magnetoresistive reference units are electrically connected to form a reference arm. The sensing arm and the reference arm are electrically interconnected to form a referenced bridge structure. The magnetoresistive sensing units and the magnetoresistive reference units may be AMR units having the same magnetic multilayer thin film structure, GMR spin valves, or GMR multilayer film stacks having the same magnetic multilayer thin film structure. The magnetoresistive sensing units and the magnetoresistive reference units are respectively covered with a Pd layer, and a passivating insulation layer is deposited over the Pd layer of the magnetoresistive reference units.

Abstract: A magnetic field sensor comprises a substrate and two comb-shaped soft ferromagnetic flux concentrators with an interdigitated structure formed on the substrate. The concentrators comprise N and N?1 rectangular comb teeth and corresponding comb seats wherein N is an integer greater than 1. Gaps are formed between the comb teeth of one concentrator and the comb seat of the other concentrator in an X direction. Adjacent comb teeth in a +Y direction form 2m?1 odd space gaps and 2m even space gaps. Here, m is an integer greater than zero and less than N. Push and pull magnetoresistive sensing element strings are located respectively in the odd space gaps and the even space gaps, and are electrically interconnected into a push-pull bridge. The magnetization alignment directions of the ferromagnetic pinned layer of the magnetic sensing element strings are Y direction.

Abstract: The present invention discloses a single-chip high-sensitivity magnetoresistive linear sensor, which comprises a substrate located in the X-Y plane and a soft ferromagnetic flux concentrator array located on the substrate. The soft ferromagnetic flux concentrator array comprises several soft ferromagnetic flux concentrators, wherein there is a gap between each two adjacent soft ferromagnetic flux concentrators. The +X and ?X magnetoresistive sensing unit array respectively comprises +X and ?X magnetoresistive sensing units located in the gaps. The +X and ?X magnetoresistive sensing units are electrically interconnected to form a push pull X-axis magnetoresistive sensor. Each of the magnetoresistive sensing units that have the same magnetic field sensing direction are arranged in adjacent locations. The magnetoresistive sensing units are all MTJ magnetoresistive sensor elements, and each has the same magnetic multi-layer film structure.