Microbridge-Structured Magnetoelectric Sensor Array Based on PZT/FeCoSiB Thin Films

Abstract

We present the fabrication and characterization of an array of microbridge-structured magnetoelectric (ME) thin film sensors which are constructed by an ME composite consisting of a 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> PZT film and a 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> amorphous FeCoSiB film deposited on a partially thinned Si substrate. Characterization of the sensor showed a large ME coefficient of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$16.87~\text {V/cm}\cdot \text {Oe}$ </tex-math></inline-formula> in resonance at 7.9 kHz without a charge amplifier. The sensitivity was enhanced by 1.65 times when three identical sensors were connected in series. The resonant frequency of the sensor was precisely regulated by adjusting the etched area of the substrate, and the 3 dB bandwidth of the resonant frequency was doubled after two adjusted sensors were connected in parallel.