Magnetoelectric effect from mechanically mediated torsional magnetic force effect in NdFeB magnets and shear piezoelectric effect in 0.7Pb(Mg₁/₃Nb₂/₃)O₃–0.3PbTiO₃ single crystal

Abstract

We experimentally and theoretically report the magnetoelectric effect in a composite made by sandwiching one shear mode 0.7PbMg[sub ⅓]Nb[sub ⅔]O₃-0.3PbTiO₃(PMN-PT) piezoelectric single crystal plate between two longitudinally magnetized NdFeB permanent magnet bars along the length direction of the PMN-PT plate. The magnetoelectric effect originates from the mechanically mediated product effect of the torsional magnetic force effect in the NdFeB bars and the shear piezoelectric effect in the PMN-PT plate. The composite exhibits a magnetoelectric voltage coefficient of ~32.7 mV/cm Oe with a flat frequency response in the measured range of 0.1-30 kHz. The induced magnetoelectric voltage shows a good linear relationship to the applied ac magnetic field with amplitude varying from 10[sup -7] to 10ˉ³ T. Other distinct features include no need to have a magnetostrictive phase, low Joule heating loss, and high scale-down capability. These suggest promising applications of the torsional-shear mode composite in power-free magnetic field sensors.