Low-Frequency and High-Sensitivity PVDF/Metglas Magnetoelectric Sensor Based on Bending Vibration Mode

The bending vibration modes of asymmetric magnetoelectric (ME) laminated composites operate in a low-frequency range, but the small value of the ME voltage coefficient (alpha(ME)) at bending vibration frequencies currently hinders the application of ME magnetic sensors at lower frequencies. In this study, poly(vinylidene fluoride) (PVDF) and Metglas were combined by adhesive bonding method to manufacture laminated ME composites. The average stiffness of ME composites was reduced by using vacuum packing technique to modulate the dominant vibration mode from longitudinal to bending. After treatment, the dominant resonance frequency and the DC bias field of the samples with a length of 30 mm were reduced from 51.15 kHz and 3.7 Oe to 10.59 kHz and 2.35 Oe, respectively. The alpha(ME) of the samples was significantly increased to 493.7 Vcm(-1)Oe(-1), which is approximately 2.5 times higher than that of the untreated samples. Remarkable magnetic sensing capabilities at low frequencies of the treated samples were also were found. At 10.59 kHz, the samples had a large sensitivity of 2522.33 mVOe(-1), an excellent linearity of 0.99985, and good resolutions of 0.4 nT for AC and 2.4 nT for DC magnetic fields, respectively. In addition, samples of different sizes were prepared for comparison. The experimental results obtained from these samples were consistent with those of the original samples. These findings highlight the effectiveness of reducing the average stiffness of composites through the vacuum packing technique in reducing the resonance frequency, optimizing the bias field, and increasing the alpha(ME) value. This technique provides a valuable approach to the development of low-frequency and highly sensitive magnetic field sensors.