Highly sensitive low field Lorentz-force MEMS magnetometer

Sofiane Ben Mbarek,Mohammad I Younis,Nouha Alcheikh,Hassen M Ouakad

doi:10.1038/s41598-021-01171-z

Sofiane Ben Mbarek, Mohammad I Younis + Show 2 more

Open Access

https://doi.org/10.1038/s41598-021-01171-z

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Abstract

We present a highly sensitive Lorentz-force magnetic micro-sensor capable of measuring low field values. The magnetometer consists of a silicon micro-beam sandwiched between two electrodes to electrostatically induce in-plane vibration and to detect the output current. The method is based on measuring the resonance frequency of the micro-beam around the buckling zone to sense out-of-plane magnetic fields. When biased with a current of 0.91 mA (around buckling), the device has a measured sensitivity of 11.6 T−1, which is five orders of magnitude larger than the state-of-the-art. The measured minimum detectable magnetic field and the estimated resolution of the proposed magnetic sensor are 100 µT and 13.6 µT.Hz−1/2, respectively. An analytical model is developed based on the Euler–Bernoulli beam theory and the Galerkin discretization to understand and verify the micro-sensor performance. Good agreement is shown between analytical results and experimental data. Furthermore, the presented magnetometer is promising for measuring very weak biomagnetic fields.

Highlights

We present a highly sensitive Lorentz-force magnetic micro-sensor capable of measuring low field values
The significant improvement in the performance of magnetic sensors, such as excellent sensitivity, high resolution, minimum detectable magnetic field, low power consumption, high stability, wide bandwidth, small size, low cost, and excellent linearity, has allowed them to be used in navigation (1 nT–600 μT), biomagnetic (100 fT–0.1 μT), and archeology (1 pT–700 μT) applications[5]
Micro-electromechanical Systems (MEMS) magnetometers with low power consumption and low cost have emerged as a promising a lternative[11,12,13]

Summary

Introduction

We present a highly sensitive Lorentz-force magnetic micro-sensor capable of measuring low field values. We presented a miniature highly sensitive wide-range resonant magnetic Lorentz-force micro-sensor based on measuring the resonance frequency of straight heated microbeam operating around the buckling zone[36]. To further analyze the effect of the operating current on the sensitivity, Fig. 4c illustrates the analytical and experimental results of S with ITh before the buckling zone.

Results

Conclusion