The invention relates to a method for determining a coupling between magnetometers of an array of N magnetometers, for example with optical pumping, where each magnetometer comprises a field cancellation system capable of being activated to operate the magnetometer in zero field. This method comprises a first phase (P1) during which the N magnetometers are separated into N−1 magnetometers whose field cancellation system is deactivated and a measuring magnetometer whose field cancellation system is activated. This first phase comprises: the generation (GENj), by the magnetometers, of a plurality of reference magnetic fields of known amplitudes and distinct directions, the measurement (MESi), by the measuring magnetometer, of the ambient magnetic field on a plurality of measurement axes determination (CALCij) of coupling coefficients between the measuring magnetometer and each of the N magnetometers from said measurement and said known amplitudes.

Methods and apparatuses to obtain increased performance and differentiation for an inductive position sensor through improvements to the sense element and target design are disclosed. In a particular embodiment, a sense element includes a transmit coil, a first receive coil that includes a first plurality of arrayed loops, wherein two or more of the first plurality of arrayed loops are at least one of phase blended and amplitude arrayed, and a second receive coil that includes a second plurality of arrayed loops, wherein two or more of the second plurality of arrayed loops are at least one of phase blended and amplitude arrayed, and wherein the first receive coil and the second receive coil are phase shifted. The sense element coils are arrayed in several geometries and layouts, and the coil and target geometry are manipulated to compensate for inherent errors in the fundamental design of an inductive position sensor.

A digital compass with two or more multi-axis magnetometers and a processing element to determine a heading and detect any offset error in the heading is described. One electronic device includes first and second magnetometers. The second magnetometer can be disposed at least a specified distance or co-located and offset at least a specified angle from the first magnetometer. A processing device determines a magnetic field at the electronic device using a first output from the first magnetometer, detects an offset error in the magnetic field using a second output from the second magnetometer, and reports the offset error in the magnetic field.

A magnetic field angle sensor includes a coil configured to generate a magnetic field that induces an eddy current in a rotatable target, a first magnetic field sensing structure positioned proximate to the coil and configured to detect a reflected magnetic field generated by the eddy current induced in the target, a second magnetic field sensing structure positioned proximate to the coil and configured to detect the reflected magnetic field generated by the eddy current induced in the target, wherein the first and second magnetic field sensing structures are configured to detect quadrature components of the reflected magnetic field, and a processing module configured to process the reflected magnetic field detected by the first and second magnetic field sensing structures for determining an angular position of the target.

A magnetic sensor whose output characteristic is less sensitive to the environmental temperature is provided. Magnetic sensor 1 has free layer 24 whose magnetization direction changes in response to an external magnetic field, pinned layer 22 whose magnetization direction is fixed with respect to the external magnetic field, spacer layer 23 that is located between pinned layer 22 and free layer 24 and that exhibits a magnetoresistance effect, and at least one magnet film 25 that applies a bias magnetic field to free layer 24. The film thickness of the magnet film is 15 nm or more and 50 nm or less. The relationship of 0.7≤T.sub.C_HM/T.sub.C_FL≤1.05 is satisfied, where T.sub.C_HM is Curie temperature of the magnet film, and T.sub.C_FL is Curie temperature of the free layer.

A measurement apparatus includes: a memory; and a processor coupled to the memory and configured to: acquire, for each of two samples which are objects made of a same material, have different sizes, and have similar shapes, magnetization curve data measured for the sample and a shape parameter including a dimension of the sample; calculate magnetization of an inner part of each of the samples based on the acquired magnetization curve data and shape parameter of the sample by using a model representing magnetization of the object by separating the magnetization of the object into a magnetization component of a surface part and a magnetization component of an inner part of the object in accordance with a volume ratio between the surface part and the inner part of the object; and output the calculated result.

A magnetic read head is provided, comprising a bottom magnetic shield, a first free magnetic layer, a second free magnetic layer, and a top magnetic shield, arranged from bottom to top in this order in a stacking direction from a leading side to a trailing side of the read head. A non-soft bias layer is positioned below the top magnetic shield and on a back side of the first and the second free magnetic layers. The top magnetic shield has a unidirectional anisotropy, the magnetic moments of the top and the bottom magnetic shields are canted relative to a plane of the first and the second free magnetic layers, and the top and the bottom magnetic shields are decoupled from the non-soft bias layer and not magnetically coupled to a soft bias layer.

An apparatus for magnetic field detection comprises a plurality of magnetic field sensitive devices comprising at least a first magnetic field sensitive device, a second magnetic field sensitive device and a third magnetic field sensitive device. The apparatus comprises a power source configured to provide a first supply current through the first magnetic field sensitive device and a second supply current independent of the first supply current through the second magnetic field sensitive device. The first to third magnetic field sensitive devices are coupled such that the first supply current flows through the first magnetic field sensitive device and not through the second magnetic field sensitive device, the second supply current flows through the second magnetic field sensitive device and not through the first magnetic field sensitive device, and a sum of the first supply current and the second supply current flows through the third magnetic field sensitive device.

Methods and apparatus for a magnetic sensor having a die and sensor circuitry formed in a device layer of the die with a coil integrated with the die to generate a magnetic field. A magnetoresistive magnetic field sensing element on the die detects changes in the magnetic field generated by the coil as a result of the presence of a ferromagnetic target. The sensor circuitry may process the changes in the magnetic field generated by the coil.

A magnet-based angular displacement measuring system for detecting a rotational movement of a driveshaft. The magnet-based angular displacement measuring system includes the driveshaft which includes an axial first shaft end region. The axial first shaft end region includes a magnetically non-conductive material. An exciter unit is rotationally coupled to the axial first shaft end region of the driveshaft. A stationary sensor unit functionally cooperates with the exciter unit to detect a rotational movement of the driveshaft.