Wide-bandwidth high-sensitivity magnetoelectric effect of magnetostrictive/piezoelectric composites under adjustable bias voltage

This paper presents a wide-bandwidth high-sensitivity magnetostrictive/piezoelectric magnetoelectric (ME) composite (PZT-5/Terfenol-D/PZT-8). The resonant frequencies of the ME laminate structure can be adjusted by modulating the bias voltage across PZT-5 layer. Model and methods for the resonant ME effects in laminate composites under adjustable bias voltages are presented. The relationships between the control voltage, the strain, the Young's modulus, the first-order resonant frequencies and the resonant ME coefficient are analyzed. Theoretical analyses show that the first-order resonant frequencies of the laminate structure are almost a linear function of the applied dc bias voltage at a small strain. The ME coefficient is hardly related to the control voltage. The experimental results are in good agreement with the analytical results. For a control voltage of ±170 V, the first-order resonant frequencies can be linearly adjusted. The adjusted maximum of the resonant frequency is 1 kHz. The ratio of the adjusted value to the bias control voltage is 2.94 Hz/V. For the larger control voltage (such as ±350 V), the wider adjusted resonant frequency (over 2 kHz or 1.73%) can be obtained. Thus, the ME composite with a high sensitivity and a wide frequency bandwidth can be used in ME transducer and energy harvesting.