Allegro Microsystems, LLC

Crocus-technology Sa

Andrey Timopheev

Jeffrey Childress

Nikita Strelkov

Ali Alaoui

Clarisse Ducruet

Léa Cuchet

Salim Dounia

Romain Foissac

Evgeny Burmistrov

A magnetoresistive element comprising a reference layer, a ferromagnetic sense layer having a free sense magnetization, and a tunnel barrier layer between the reference layer and the sense layer. The sense layer comprises a first sense layer portion in contact with the tunnel barrier layer and a second sense layer portion in contact with the first sense layer portion. The first sense layer portion is configured such that a magnetic coupling between the first and second sense layer portions is between ±10J/mand ±10J/m; and a perpendicular magnetic anisotropy (PMA) originating from the interface between the first sense layer portion and the tunnel barrier layer is between 8×10A/m and 8×10A/m, such as to shift positively the TCS of the magnetoresistive element and compensate the negative temperature coefficient of TMR of the magnetoresistive element.

Magnetoresistive element having compensated temperature coefficient of TMR

A magnetoresistive element has a tunnel barrier layer included between a ferromagnetic reference layer having a fixed reference magnetization and a ferromagnetic sense layer having a free sense magnetization. The sense magnetization has a ferromagnetic material composition and a stable vortex configuration in the absence of an applied magnetic field. The ferromagnetic material composition varies across the thickness of the sense layer from a composition with higher magnetization near the tunnel barrier layer to a composition with lower magnetization away from the tunnel barrier layer, such that the sense magnetization and ferromagnetic exchange strength of the sense layer are higher near the tunnel barrier layer than away from the tunnel barrier layer.

Magnetoresistive element and magnetic sensor device having a high sensitivity and low zero-field offset-shift

A magnetoresistive sensor element including: a reference layer having a pinned reference magnetization; a sense layer having a free sense magnetization comprising a stable vortex configuration reversibly movable in accordance to an external magnetic field to be measured; a tunnel barrier layer between the reference layer and the sense layer; wherein the sense layer includes a first ferromagnetic sense portion in contact with the tunnel barrier layer and a second ferromagnetic sense portion in contact with the first ferromagnetic sense portion; the second ferromagnetic sense portion including a dilution element in a proportion such that a temperature dependence of a magnetic susceptibility of the sense layer substantially compensates a temperature dependence of a tunnel magnetoresistance of the magnetoresistive sensor element. Also, a method for manufacturing the magnetoresistive sensor element.

Magnetoresistive sensor element having compensated temperature coefficient of sensitivity and method for manufacturing said element

Magnetic angular sensor element destined to sense an external magnetic field, including a magnetic tunnel junction containing a ferromagnetic pinned layer having a pinned magnetization, a ferromagnetic sensing layer, and a tunnel magnetoresistance barrier layer; the ferromagnetic sensing layer including a first sensing layer being in direct contact with the barrier layer and having a first sensing magnetization, a second sensing layer having a second sense magnetization, and a metallic spacer between the first sensing layer and the second sensing layer; wherein the metallic spacer is configured to provide an antiferromagnetic coupling between the first sensing magnetization and the second sensing magnetization such that the first sensing magnetization is oriented substantially antiparallel to the second sensing magnetization; the second sensing magnetization being larger than the first sensing magnetization, such that the second sensing magnetization is oriented in accordance with the direction of the external magnetic field.

Magnetic sensor element and device having improved accuracy under high magnetic fields

A magnetoresistive element for a magnetic sensor, the magnetoresistive element including a tunnel barrier layer between a reference layer having a fixed reference magnetization and a sense layer having a free sense magnetization, wherein the sense magnetization includes a stable vortex configuration. The magnetoresistive element further includes a reference pinning layer in contact with the reference layer and pining the reference magnetization by exchange-bias at a first blocking temperature. The magnetoresistive element further includes a sense pinning layer in contact with the sense layer and pining the sense magnetization by exchange-bias at a second blocking temperature lower that the first blocking temperature. Additionally, a method for manufacturing the magnetoresistive element.

Magnetoresistive sensor element having a wide linear response and robust nominal performance and manufacturing method thereof

A magnetoresistive element for a 2D magnetic sensor, the magnetoresistive element including a tunnel barrier layer included between a reference layer having a reference magnetization and a sense layer having a sense magnetization. The sense layer includes a sense synthetic antiferromagnetic structure including a first sense sublayer in contact with the tunnel barrier layer and separated from a second sense sublayer by a first non-magnetic spacer layer such that the first sense sublayer is antiferromagnetically coupled to the second sense sublayer. The sense layer is configured such that a sense magnetic ratio ΔM defined as: wherein Mand Mare the spontaneous magnetizations of the first and second sense sublayers and tand tare the thicknesses of the first and second sense sublayers; and wherein the sense magnetic ratio is between 0.1 and 0.25.

Magnetoresistive element for a 2D magnetic sensor having a reduced hysteresis response

A magnetic sensor including a plurality of magnetoresistive elements; each magnetoresistive element including a ferromagnetic layer having a magnetization that is orientable at or above a threshold temperature; the magnetic sensor further includes a plasmonic structure destined to be irradiated by electromagnetic radiation and including a spatially periodic plasmonic array of metallic structures. The period of the plasmonic array and the lateral dimension of the metallic structures are adjusted to obtain plasmon resonance of the plasmonic structure for a given wavelength of the electromagnetic radiation. The plasmonic array is arranged in the magnetic sensor such as to heat the first ferromagnetic layer at or above the threshold temperature, from the enhanced absorption of the electromagnetic radiation by plasmon resonance. The present disclosure further concerns a system including the sensor and an emitting device configured to emit electromagnetic radiation.

Magnetic sensor comprising magnetoresistive elements and system for programming such magnetic sensor

An electronic circuit for measuring an angle and an intensity of an external magnetic field, includes: first and second magnetic field sensing units having sensing axes substantially orthogonal to each other; a voltage generator supplying a synchronization signal, a first voltage waveform to the first magnetic field sensing unit and a second voltage waveform to the second magnetic field sensing unit; a signal conditioning unit configured for adding the first and second sensing output signals and outputting a conditioned signal. The first and second voltage waveforms have substantially the same amplitude and frequency and are phase shifted by about 90° with respect to each other. The conditioned signal and the synchronization signal are inputted into a magnetic field angle detection unit configured for measuring a phase shift between the conditioned signal and the synchronization signal and for determining the angle of the external magnetic field from the measured phase shift.

Electronic circuit for measuring an angle and an intensity of an external magnetic field

Magnetic current sensor, including: a sensor bridge circuit including a first and second half-bridges, each including two series-connected and diagonally opposed tunnel magnetoresistive (TMR) sensor elements, the TMR sensor elements including a reference layer oriented a single predetermined direction and a sense layer having a sense magnetization; a field line configured for passing a field current generating a magnetic field adapted for orienting the sense magnetization of the diagonally opposed TMR sensor elements of the first half-bridge and of the diagonally opposed TMR sensor elements of the second half-bridge in an opposite direction; such that a non-null differential voltage output between the TMR sensor elements of the first half-bridge and the TMR sensor elements of the second half-bridge is measurable when the field current is passed in the field line; the differential voltage output being insensitive to the presence of an external uniform magnetic field.

Magnetic current sensor comprising a magnetoresistive differential full bridge

Magnetic angular sensor device destined to sense an external magnetic field, the sensor device including a plurality of magnetic sensor elements, each sensor element including a magnetic tunnel junction containing a ferromagnetic reference layer having a reference magnetization that is pinned in a pinning direction, a ferromagnetic sense layer having a sense magnetization that can be oriented in an external magnetic field, and a tunnel barrier spacer layer, between the reference layer and the sense layer; wherein the sense layer of at least a portion of said plurality of sensor elements comprises an in-plane uniaxial sense magnetic anisotropy having an easy axis that is aligned substantially parallel to the pinning direction, such that an angular deviation in the alignment of the direction of the sense magnetization in the external magnetic field is minimized for a range of external magnetic field.

Magnetic angular sensor device for sensing high magnetic fields with low angular error

A magnetic sensing circuit includes a circuit portion including: a main half-bridge including series-connected main tunnel magnetoresistive sensor elements TMRand TMR; a first auxiliary half-bridge connected in parallel to the main half-bridge and including series-connected auxiliary tunnel magnetoresistive sensor elements TMRand TMRwith an output voltage emerging from the connection between TMRand TMRand between TMRand TMR; wherein a reference magnetization of the magnetoresistive sensor element TMRand TMRare respectively oriented substantially antiparallel with respect to a reference magnetization of the magnetoresistive sensor element TMRand TMR; and wherein said first auxiliary half-bridge has a sensing axis that differs from the sensing axis of the main half bridge by an angle of about 180&#xb0;/n, where n is the harmonic number to be canceled. The magnetic sensing circuit allows for sensing of external magnetic fields having high magnitude, with reduced angular error.

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Vif, France

Andrey Timopheev