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1. (WO2018183673) TUNNEL MAGNETO-RESISTIVE (TMR) SENSORS EMPLOYING TMR DEVICES WITH DIFFERENT MAGNETIC FIELD SENSITIVITIES FOR INCREASED DETECTION SENSITIVITY

Pub. No.:    WO/2018/183673    International Application No.:    PCT/US2018/025141
Publication Date: Fri Oct 05 01:59:59 CEST 2018 International Filing Date: Fri Mar 30 01:59:59 CEST 2018
IPC: G01R 33/09
G01R 33/12
Applicants: QUALCOMM INCORPORATED
Inventors: CHEN, Wei-Chuan
HSU, Wah Nam
LI, Xia
KANG, Seung, Hyuk
STEVENS-YU, Nicholas, Ka Ming
Title: TUNNEL MAGNETO-RESISTIVE (TMR) SENSORS EMPLOYING TMR DEVICES WITH DIFFERENT MAGNETIC FIELD SENSITIVITIES FOR INCREASED DETECTION SENSITIVITY
Abstract:
Tunnel magneto-resistive (TMR) sensors employing TMR devices with different magnetic field sensitivities for increased detection sensitivity are disclosed. For example, a TMR sensor may be used as a biosensor to detect the presence of biological materials. In aspects disclosed herein, free layers of at least two TMR devices in a TMR sensor are fabricated to exhibit different magnetic properties from each other (e.g., MR ratio, magnetic anisotropy, coercivity) so that each TMR device will exhibit a different change in resistance to a given magnetic stray field for increased magnetic field detection sensitivity. For example, the TMR devices may be fabricated to exhibit different magnetic properties such that one TMR device exhibits a greater change in resistance in the presence of a smaller magnetic stray field, and another TMR device exhibits a greater change in resistance in the presence of a larger magnetic stray field.