Ultrasensitive Magneto electric Sensor based on Galfenol/ AlN structure

Abstract

Abstract Ultrasensitive magnetic field sensors based on magnetoelectric (ME) structures have many applications in bio-magnetic sensors and magnetoencephalography (MEG) scanners. Enhance the sensitivity, limit of detection and main frequency of these sensors need simulation process by accurate methods such as finite element method (FEM). To get good sensitivity and efficient benefit, we use a cantilever-type composite structures including galfenol alloy as a magnetostrictive layer and AlN as a piezoelectric layer. Galfenol is an alloy of iron and gallium and its \({\text{Fe}}_{\text{0.83}}{\text{Ga}}_{\text{0.17}}\) structure has a high magnetostriction coefficient and can be used as a thin film. According to the cantilever structure, the maximum bending of the structure is 20 \(\text{μm}\). The simulated sensor has a limit of detections of 1 \(\raisebox{1ex}{$\text{pT}$}\!\left/ \!\raisebox{-1ex}{$\sqrt{\text{Hz}}$}\right.\) and can measure an AC magnetic field of 1 pT. This sensor has the best performance in the bias DC magnetic field of 2.3 mT and resonance frequency of 2521.8 Hz and has a magnetoelectric coefficient of 4865 (\(\raisebox{1ex}{$\text{V}$}\!\left/ \!\raisebox{-1ex}{$\text{cm.Oe}$}\right.\)).