High-precision micro-displacement sensor based on tunnel magneto-resistance effect

Xuhu Wang,Yi Ruan,Chunhong Guo,Meimei Gong,Chenguang Xin,Junqiang Wang,Li Jin,Yujie Zhong,Wang Li,Mengwei Li

doi:10.1038/s41598-022-06965-3

Xuhu Wang, Yi Ruan + Show 8 more

Open Access

https://doi.org/10.1038/s41598-022-06965-3

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Journal: Scientific Reports	Publication Date: Feb 22, 2022
Citations: 3	License type: open-access

Affiliation: North University of China, Nantong University

Abstract

A high-precision micro-displacement sensor based on tunnel magneto-resistance effect is reported.We designed and simulated magnetic characteristics of the sensor, and employed chip-level Au-In bonding to implement low-temperature assembly of the TMR devices. We employed the subdivision interpolation technique to enhance the resolution by translating the sine-cosine outputs of a TMR sensor into an output that varies linearly with the displacement. Simultaneously, using the multi-bridge circuit method to suppress external magnetic and geomagnetic interference. Experimental result shows that the micro-displacement sensor has a resolution of 800 nm, accuracy of 0.14% and a full-scale range of up to millimeter level. This work enables a high-performance displacement sensor, and provides a significant guide for the design of a micro-displacement sensor in practical applications.

Highlights

A high-precision micro-displacement sensor based on tunnel magneto-resistance effect is reported
V = − KAV0 sin π(2y + d) sin π d where V0 is the static voltage and R0 is the static resistance of the tunnel magneto-resistance (TMR), K is the sensitivity of the TMR devices, A is the amplitude of magnetic feld, D is the line spacing of electric coils, d is the spacing distance of the adjacent bridge circuits and y is the displacement along the sense direction
Due to the distribution of the magnetic field is a quasi-sine function curve in the sense direction, we arrange TMRs of the bridge circuits equidistant and the spacing distance is designed to a quarter of the period of the sinusoidal magnetic field

Summary

Introduction

A high-precision micro-displacement sensor based on tunnel magneto-resistance effect is reported. A displacement sensor based on tunnel magneto-resistance (TMR) effect with sub-micrometer level resolution and millimeter level of operation range is demonstrated.

Results

Conclusion