Magnetic sensor employing piezoelectric ceramic/rare-earth iron alloy/high-permeability FeCuNbSiB composite

The magnetic sensor employing Terfenol-D/PZT/FeCuNbSiB (MPF) magnetoelectric (ME) laminate is investigated. The high permeability of FeCuNbSiB can concentrate the magnetic flux and enhance the effective dynamic strain coefficient in Terfenol-D, consequently resulting in the increase of the dynamic ME voltage coefficient (MEVC) (i.e., dV_ME/dH_ac under dc bias field) and the ME voltage sensitivity to H_dc (i.e., dV_ME/dH_dc under ac bias field denoted as the static MEVC). The experimental results show that the Terfenol-D/FeCuNbSiB (MF) laminate exhibits a 1-2 times higher dynamic strain coefficient than that of a single Terfenol-D near resonance under a low H_dc. The dynamic MEVC for the MPF sensor achieves 2.185V/Oe. In addition, the maximum static MEVC achieves ~125mV/Oe under a resonant drive, which is 5 times as high as that of Terfenol-D/PZT (MP) sensor. Thus the MPF sensor can detect either dynamic or static magnetic fields. It is found that the thickness of the high permeability layer is critical to the composite sensor performances.