Highly Integrated MEMS Magnetic Sensor Based on GMI Effect of Amorphous Wire.

Jiawen Chen,Jianhua Li,Lixin Xu

doi:10.3390/mi10040237

Jiawen Chen, Jianhua Li + Show 1 more

Open Access

https://doi.org/10.3390/mi10040237

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Journal: Micromachines	Publication Date: Apr 8, 2019
Citations: 25	License type: CC BY 4.0

Affiliation: Beijing Institute of Technology

Abstract

In this paper, a highly integrated amorphous wire Giant magneto-impedance (GMI) magnetic sensor using micro electron mechanical system (MEMS) technology is designed, which is equipped with a signal conditioning circuit and uses a data acquisition card to convert the output signal of the circuit into a digital signal. The structure and package of the sensor are introduced. The sensor sensing principle and signal conditioning circuit are analyzed. The output of the sensor is tested, calibrated, and the relationship between the GMI effect of the amorphous wire and the excitation current frequency is explored. The sensor supplies voltage is ±5 V, and the excitation signal is a square wave signal with a frequency of 60 MHz and an amplitude of 1.2 V generated by the quartz crystal. The sensor has the largest GMI effect at 60 MHz with a sensitivity of 4.8 V/Oe and a resolution of 40 nT.

Highlights

Since Mohri et al found the Giant magneto-impedance (GMI) effect with its large sensitivity of the electrical impedance in amorphous materials, the continuous study of developing new materials and special treatments to design GMI sensors has become one of intensive research in the field of weak magnetic measurements [1,2,3,4]
Amorphous GMI sensors find a wide range of applications in areas such as security electronics, recording heads, and recently, life science [5]
Sergey Gudoshnikov et al designed a magnetometer based on the off-diagonal GMI effect in Co-rich glass-coated amorphous wire [8]

Summary

Introduction

Since Mohri et al found the Giant magneto-impedance (GMI) effect with its large sensitivity of the electrical impedance in amorphous materials, the continuous study of developing new materials and special treatments to design GMI sensors has become one of intensive research in the field of weak magnetic measurements [1,2,3,4]. The detector was at a low power consumption with a simple circuit structure It had a wide linear range of ±3 Oe and high magnetic sensitivity of 65 mV/Oe. Xinhua Nie et al developed a differential-type integrating GMI magnetic sensor [11]. Kaneo Mohri et al developed an amorphous wire CMOS integrated circuit (IC) multi-vibrator type micro-linear magnetic field sensor for industrial usage MI sensor chip [14]. Yulong Chen et al presented a novel fabrication method for amorphous alloy wire GMI magnetic sensor based on MEMS technology [17] In this process, negative SU-8 thick photoresist was proposed as the solder mask due to its excellent properties and the low melting temperature solder paste was used for the electrical connections with the amorphous alloy wire and the electrode pads.

Fabrication Method

Findings

Device Design