Abstract: A method for measuring relative concentrations of materials in a mixture includes providing an emission coil and at least one reception coil, providing a mixture with n materials having different magnetic susceptibilities, and introducing the mixture into the reception coil. Using a voltage generator the emission coil is supplied with at least one nonzero excitation frequency so as to generate an excitation magnetic field and the signal of the voltage induced in the reception coil is measured. Relative concentrations of the n materials are determined based on comparison between the overall susceptibility of the mixture as obtained through the voltage measurement and that of a reference mixture for which the relative concentrations of the n materials are known.

Abstract: Methods and apparatus for an MR device having a ferromagnetic material, a heavy metal layer configured to flow a charge current, and an insulating layer between the ferromagnetic material and the heavy metal layer. The insulating layer is configured to electrically insulate and to magnetically couple the heavy metal layer and the ferromagnetic layer for generating a field like (FL) field in the ferromagnetic material in response to the charge current. In some embodiments, the MR device comprises a TMR device having a free layer or a reference layer oriented by the charge current. In other embodiments, the MR device comprises a GMR device.

Abstract: A magnetoresistive stack includes a reference layer including a magnetic layer, an antiferromagnetic layer in exchange coupling with the magnetic layer, a magnetic layer substantially of the same magnetisation as the magnetic layer, a spacer layer between the magnetic layers with a thickness for enabling an antiferromagnetic coupling between the magnetic layers of a first coupling intensity, a free layer having a coercivity of less than 10 microTesla, the free layer including a magnetic layer, an antiferromagnetic layer in exchange coupling with the magnetic layer, a magnetic layer substantially of the same magnetisation as the magnetic layer, a spacer layer between the magnetic layers with a thickness for enabling an antiferromagnetic coupling between the magnetic layers of a second coupling intensity lower than the first coupling intensity, a third spacer layer separating the reference and free layers.

Abstract: Methods and apparatus for an MR device having a ferromagnetic material, a heavy metal layer configured to flow a charge current, and an insulating layer between the ferromagnetic material and the heavy metal layer. The insulating layer is configured to electrically insulate and to magnetically couple the heavy metal layer and the ferromagnetic layer for generating a field like (FL) field in the ferromagnetic material in response to the charge current. In some embodiments, the MR device comprises a TMR device having a free layer or a reference layer oriented by the charge current. In other embodiments, the MR device comprises a GMR device.

Abstract: A method for measuring relative concentrations of materials in a mixture includes providing an emission coil and at least one reception coil, providing a mixture with n materials having different magnetic susceptibilities, and introducing the mixture into the reception coil. Using a voltage generator the emission coil is supplied with at least one nonzero excitation frequency so as to generate an excitation magnetic field and the signal of the voltage induced in the reception coil is measured. Relative concentrations of the n materials are determined based on comparison between the overall susceptibility of the mixture as obtained through the voltage measurement and that of a reference mixture for which the relative concentrations of the n materials are known.

Abstract: A device for magnetically detecting microscopic biological objects includes a microfluidic channel having a fluid inlet and a fluid outlet; a plurality of magnetic sensors arranged against an inner wall of the microfluidic channel; and a permanent magnet arranged against an outer wall of the microfluidic channel, in such a way that the plurality of magnetic sensors is immersed in a magnetic field created by the permanent magnet; the plurality of magnetic sensors including a first magnetic sensor; a second magnetic sensor opposite the first magnetic sensor; a third magnetic sensor downstream of the first and second magnetic sensors.

Abstract: A magnetic field sensor includes a first coil responsive to a first AC coil drive signal having a first frequency, a magnetic field sensing element responsive to a sensing element drive signal and configured to simultaneously detect a directly coupled magnetic field generated by the first coil and a reflected magnetic field generated by an eddy current induced in a conductive target by the first coil, the conductive target disposed proximate to the magnetic field sensing element, the magnetic field sensing element further configured to generate a magnetic field signal, a second coil responsive to a second AC coil drive signal having a second frequency that is the same as the first frequency and current sensing circuitry configured to measure a magnitude of the second AC coil drive signal that causes the magnetic field signal to be approximately zero.

Abstract: A system for suppressing low frequency magnetic noise from magnetoresistive sensors, the system including at least one magneto-resistive sensor including a free magnetic layer having a variable magnetisation, and a system for modifying magnetisation of the free magnetic layer, wherein the system for modifying magnetisation of the free layer is adapted to drive dynamics of the magnetisation of the free magnetic layer.

Abstract: A magnetic field sensor includes at least one coil responsive to an AC coil drive signal; at least one magnetic field sensing element responsive to a sensing element drive signal and configured to detect a directly coupled magnetic field generated by the at least one coil and to generate a magnetic field signal in response to the directly coupled magnetic field; a processor responsive to the magnetic field signal to compute a sensitivity value associated with detection of the directly coupled magnetic field and substantially independent of a reflected magnetic field reflected by a conductive target disposed proximate to the at least one magnetic field sensing element; and an output signal generator configured to generate an output signal of the magnetic field sensor indicative of the reflected magnetic field.

Abstract: A magnetoresistive stack includes a reference layer including a magnetic layer, an antiferromagnetic layer in exchange coupling with the magnetic layer, a magnetic layer substantially of the same magnetisation as the magnetic layer, a spacer layer between the magnetic layers with a thickness for enabling an antiferromagnetic coupling between the magnetic layers of a first coupling intensity, a free layer having a coercivity of less than 10 microTesla, the free layer including a magnetic layer, an antiferromagnetic layer in exchange coupling with the magnetic layer, a magnetic layer substantially of the same magnetisation as the magnetic layer, a spacer layer between the magnetic layers with a thickness for enabling an antiferromagnetic coupling between the magnetic layers of a second coupling intensity lower than the first coupling intensity, a third spacer layer separating the reference and free layers.

Abstract: A magnetic field sensor includes at least one coil responsive to an AC coil drive signal; at least one magnetic field sensing element responsive to a sensing element drive signal and configured to detect a directly coupled magnetic field generated by the at least one coil and to generate a magnetic field signal in response to the directly coupled magnetic field; a processor responsive to the magnetic field signal to compute a sensitivity value associated with detection of the directly coupled magnetic field and substantially independent of a reflected magnetic field reflected by a conductive target disposed proximate to the at least one magnetic field sensing element; and an output signal generator configured to generate an output signal of the magnetic field sensor indicative of the reflected magnetic field.

Abstract: A magnetic field sensor includes at least one coil responsive to an AC coil drive signal; at least one magnetic field sensing element responsive to a sensing element drive signal and configured to detect a directly coupled magnetic field generated by the at least one coil and to generate a magnetic field signal in response to the directly coupled magnetic field; a processor responsive to the magnetic field signal to compute a sensitivity value associated with detection of the directly coupled magnetic field and substantially independent of a reflected magnetic field reflected by a conductive target disposed proximate to the at least one magnetic field sensing element; and an output signal generator configured to generate an output signal of the magnetic field sensor indicative of the reflected magnetic field.

Abstract: Apparatus includes a first portion of conductive material having varying response to a generated magnetic field along a length of the conductive material, wherein the first portion of conductive material produces a varying eddy current and a varying reflected magnetic field, in response to the generated magnetic field. The apparatus further includes one or more reference portions of conductive material having a relatively invariable response to the generated magnetic field, wherein the reference portion of conductive material produces a relatively invariable eddy current and a relatively invariable reflected magnetic field in response to the generated magnetic field.

Abstract: A system for suppressing low frequency noise of magnetoresistive sensors, includes a device for measuring a magnetic field, the device including at least one magnetoresistive sensor, the magnetoresistive sensor having a first sensitivity at a first operating point and a second sensitivity at a second operating point, the sensitivity at the second operating point being low or zero; a modulator configured to switch the at least one magnetoresistive sensor from the first operating point to the second operating point; and a signal processor for processing the signal derived from the device for measuring a magnetic field.

Abstract: A system for suppressing low frequency noise of magnetoresistive sensors, includes a device for measuring a magnetic field, the device including at least one magnetoresistive sensor, the magnetoresistive sensor having a first sensitivity at a first operating point and a second sensitivity at a second operating point, the sensitivity at the second operating point being low or zero; a modulator configured to switch the at least one magnetoresistive sensor from the first operating point to the second operating point; and a signal processor for processing the signal derived from the device for measuring a magnetic field.

Abstract: In one aspect, a magnetic field angle sensor includes a bridge structure that include a sine bridge configured to generate a sinusoidal signal indicative of a magnetic field along a first axis and a cosine bridge configured to generate a cosinusoidal signal indicative of the magnetic field along a second axis that is orthogonal with respect to the first axis. One of the sine bridge or the cosine bridge includes a first set of at least two magnetoresistance elements, a second set of at least one magnetoresistance element, a third set of at least one magnetoresistance element and a fourth set of at least one magnetoresistance element. An average reference direction of the first set of at least two magnetoresistance elements is equal to an average reference direction of the third set of at least one magnetoresistance element.

Abstract: A magnetoresistance assembly can include a substrate and a first GMR element disposed over the substrate, the first GMR element having a bottom surface and top surface. The magnetoresistance assembly can further include a first TMR element disposed over the substrate, the first TMR element having a top surface and a bottom surface, wherein a line perpendicular to and intersecting the top or bottom surface of the first TMR element intersects the first GMR element. The first GMR element and the first TMR element are in electrical communication.

Abstract: Methods and apparatus for providing data transfer with a drive coil to transmit information, a receive coil magnetically coupled to the drive coil, and a first magnetoresistive sensor proximate the receive coil to detect information from the receive coil. In embodiments, the drive and receive coils are separated by an isolation material. In embodiments, a signal isolator IC packages includes transmit and receive coils and a magnetic field sensing element coupled to the receive coil.

Abstract: A device for magnetically detecting microscopic biological objects includes a microfluidic channel having a fluid inlet and a fluid outlet; a plurality of magnetic sensors arranged against an inner wall of the microfluidic channel; and a permanent magnet arranged against an outer wall of the microfluidic channel, in such a way that the plurality of magnetic sensors is immersed in a magnetic field created by the permanent magnet; the plurality of magnetic sensors including a first magnetic sensor; a second magnetic sensor opposite the first magnetic sensor; a third magnetic sensor downstream of the first and second magnetic sensors.

Abstract: A system for suppressing low frequency noise of magnetoresistive sensors, includes a device for measuring a magnetic field, the device including at least one magnetoresistive sensor, the magnetoresistive sensor having a first sensitivity at a first operating point and a second sensitivity at a second operating point, the sensitivity at the second operating point being low or zero; a modulator configured to switch the at least one magnetoresistive sensor from the first operating point to the second operating point; and a signal processor for processing the signal derived from the device for measuring a magnetic field.