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 H-ac (i.e., partial derivative V-ME/partial derivative H-ac under dc bias field) and the ME voltage sensitivity to H-dc (i.e., partial derivative V-ME/partial derivative H-dc under ac bias field) for the ME sensor are significantly dependent on the product of the effective mechanical quality factor of the ME sensor Q(m), the saturation magnetostriction lambda(s) of the magnetostrictive material, and the square of magnetic permeability mu(r). The experimental results demonstrate that the greatest value of partial derivative V-ME/partial derivative H-ac for the FeCuNbSiB/PZT-8/FeCuNbSiB (FePFe) sensor reaches 10 V/Oe due to the largest product of the Q(m), lambda(s) and the square of mu(r), relative to FeNi-FACE/PZT-8/FeNi-FACE (FPF) and Terfenol-D/PZT-8/Terfenol-D (MPM) sensors. Meanwhile, the maximum value of partial derivative V-ME/partial derivative H-dc for FePFe sensor achieves 242.2 mV/Oe, which is similar to 10 times higher than that of the FPF sensor and similar to 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. (C) 2012 American Institute of Physics. [doi:10.1063/1.3670607]