Modeling and parallel operation of exchange-biased delta-E effect magnetometers for sensor arrays

Recently, Delta-E effect magnetic field sensors based on exchange-biased magnetic multi-layers have shown the potential of detecting low-frequency and small-amplitude magnetic fields. Their design is compatible with microelectromechanical system technology, potentially small, and therefore, suitable for arrays with a large number N of sensor elements. In this study, we explore the prospects and limitations for improving the detection limit by averaging the output of N sensor elements operated in parallel with a single oscillator and a single amplifier to avoid additional electronics and keep the setup compact. Measurements are performed on a two-element array of exchange-biased sensor elements to validate a signal and noise model. With the model, we estimate requirements and tolerances for sensor elements using larger N. It is found that the intrinsic noise of the sensor elements can be considered uncorrelated, and the signal amplitude is improved if the resonance frequencies differ by less than approximately half the bandwidth of the resonators. Under these conditions, the averaging results in a maximum improvement in the detection limit by a factor of√ N. A maximum N ≈ 200 exists, which depends on the read-out electronics and the sensor intrinsic noise. Overall, the results indicate that significant improvement in the limit of detection is possible, and a model is presented for optimizing the design of delta-E effect sensor arrays in the future.

Subjects

Cantilever

Delta-E effect

Exchange bias

Magnetoelectric

Magnetometer

Sensor array

DDC Class

600: Technik

Publication version

publishedVersion

Lizenz

https://creativecommons.org/licenses/by/4.0/

Name

sensors-21-07594-v3.pdf

Size

2.6 MB

Format

Adobe PDF

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Modeling and parallel operation of exchange-biased delta-E effect magnetometers for sensor arrays