DC magnetic field sensor based on electric driving and magnetic tuning in piezoelectric/magnetostrictive bilayer

摘要

A dc magnetic field sensor possessing an interestingly high electric voltage-driven, magnetic field-tuned dc magnetoelectric (ME) effect is developed based on a bilayer of Pb(Zr, Ti)O_3 piezoelectric transformer and Tb_(0.3)Dy_(0.7)Fe_(1.92) magnetostrictive substrate. The dc ME effect in the sensor, as evaluated experimentally and theoretically, is induced by driving the bilayer at its zero-field longitudinal resonance frequency (f_(r0)) using an ac electric voltage (V_(ac)) referenced at the input of the piezoelectric transformer, as well as, by tuning the field-dependent compliance and resonance characteristics of the bilayer with the dc magnetic field to be measured (H_(dc)) upon the negative-ΔE effect intrinsic in the magnetostrictive substrate. The sensor shows a good linear negative response of ac ME voltage (V_(me)) at the output of the piezoelectric transformer to a broad range of H_(dc) of 0-350 Oe under a small V_(ac) of 2.5 V peak at the designatef_(r0) of 125.3 kHz. This gives a high negative dc magnetic field sensitivity (5) of -1.58 mV/Oe.