The magnetostrictive material effects on magnetic field sensitivity for magnetoelectric sensor

The magnetic sensitivity to magnetic field for the magnetoelectric (ME) sensor is studied. Theoretical analysis predicts that the ME voltage sensitivity to Hac (i.e., ∂VME/∂Hac under dc bias field) and the ME voltage sensitivity to Hdc (i.e., ∂VME/∂Hdc under ac bias field) for the ME sensor are significantly dependent on the product of the effective mechanical quality factor of the ME sensor Qm, the saturation magnetostriction λs of the magnetostrictive material, and the square of magnetic permeability μr. The experimental results demonstrate that the greatest value of ∂VME/∂Hac for the FeCuNbSiB/PZT-8/FeCuNbSiB (FePFe) sensor reaches 10 V/Oe due to the largest product of the Qm, λs and the square of μr, relative to FeNi-FACE/PZT-8/FeNi-FACE (FPF) and Terfenol-D/PZT-8/Terfenol-D (MPM) sensors. Meanwhile, the maximum value of ∂VME/∂Hdc for FePFe sensor achieves 242.2 mV/Oe, which is ∼10 times higher than that of the FPF sensor and ∼ 4 times higher than that of the MPM sensor. To obtain the high magnetic sensitivity to dc and ac magnetic field, the mechanical quality factor, the magnetic permeability and the saturation magnetostriction should both be taken into account in selecting the suitable magnetostrictive material.