Evaluation of High-Sensitivity FeGa/PZT Stacked-Layer Magnetic Sensor

Abstract

The FeGa/PZT stacked-layer magnetic sensor was studied. The prototype sensor is 15mm long and 6mm wide with two 880μm-thick FeGa layers and a 590μm-thick PZT layer. The theoretical sensitivity using a simple model was calculated to be 69.6mV/Oe. The resonant modes were analyzed using a FEM simulator, resulting in the fundamental resonant frequency of 5.38kHz. A magnetic field was applied to the longitudinal direction of the sensor to cause a longitudinal stress magnetostrictively, which produces a piezoelectric output voltage in the PZT layer. The dependences of the magnetic sensitivity on the DC bias magnetic field were evaluated, together with the frequency characteristics and the temperature dependences. The measured sensitivity agreed roughly with the calculated one. A prototype with a single magnetostrictive layer was also fabricated and evaluated for investigating the possibility of the resonant sensor.