Mr sensors having layer orientation control using sot current

By employing SOT tuning to control the magnetic orientation of ferromagnetic layers in MR sensors, the challenges of magnetic field sensing are addressed, resulting in improved sensitivity, noise rejection, and dynamic response.

WO2025064039A1 Publication Date: 2025-03-27ALLEGRO MICROSYSTEMS LLC +1
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Patent Information

Application Number
PCT/US2024/038171
Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
Priority Date
2023-09-20
Filing Date
2024-07-16
Publication Date
2025-03-27

AI Technical Summary

Technical Problem

Existing magnetic field sensors, particularly those using spin valves, face challenges in efficiently controlling the magnetic orientation of ferromagnetic layers while maintaining effective magnetoresistance readings.

Method used

The implementation of spin-orbit torque (SOT) tuning to control the free and/or reference layer of MR sensors, utilizing a charge current injected through a heavy metal layer to create a spin current that controls the ferromagnetic layer's magnetic orientation, while maintaining electrical insulation and allowing concurrent control and reading operations.

Benefits of technology

This approach enables dynamic linearization of the sensor response, high-frequency switching of the reference layer, and efficient cancellation of external fields, thereby enhancing the sensitivity and noise rejection capabilities of the MR sensors.

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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.
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