Magnetoelectric metglas/bidomain y + 140° -cut lithium niobate composite for sensing fT magnetic fields

摘要

We investigated the magnetoelectric properties of a new laminate composite material based on y + 140 degrees-cut congruent lithium niobate piezoelectric plates with an antiparallel polarized "head-tohead" bidomain structure and metglas used as a magnetostrictive layer. A series of bidomain lithium niobate crystals were prepared by annealing under conditions of Li2O outdiffusion from LiNbO3 with a resultant growth of an inversion domain. The measured quasi-static magnetoelectric coupling coefficient achieved vertical bar alpha(E31)vertical bar = 1.9V.(cm Oe)(-1). At a bending resonance frequency of 6862 Hz, we found a giant vertical bar alpha(E31)vertical bar value up to 1704V.(cm Oe)(-1). Furthermore, the equivalent magnetic noise spectral density of the investigated composite material was only 92 fT/Hz(1/2), a record value for such a low operation frequency. The magnetic-field detection limit of the laminated composite was found to be as low as 200 fT in direct measurements without any additional shielding from external noises. Published by AIP Publishing.