Smart hybrid sensor for magnetic field and vibration detection based on PMN-PT/Terfenol-D magnetoelectric composites and suspended magnetic vibrator

A smart hybrid sensor for magnetic field and vibration detection is presented. We propose a novel structure of the hybrid sensor consisting of two longitudinally magnetized and thickness polarized mode (L–T mode) Terfenol-D alloy 0.7Pb(Mg_1/3Nb_2/3)O₃–0.3PbTiO₃ single crystal (PMN–PT) magnetoelectric laminate composites and a suspended magnetic vibrator which can convert external vibration to internal alternating magnetic field. The hybrid sensor exhibits a giant vibration responsivity of 12 V/g at 400 Hz and a useful magnetic field responsivity of 6 mV/μT at 23 Hz. The detection limit for AC acceleration and magnetic field is as low as 8.16 ng/Hz^1/2 at 400 Hz and 16.4 pT/Hz^1/2 at 23 Hz, respectively. The sensor output shows linear response with low distortion both to AC acceleration and magnetic field. In the end, the sensor's capability for detection of magnetic and non-magnetic moving target has been proven to be useful in intelligent transportation by an outdoor (open) test.