Improving the magnetoelectric performance of Metglas/PZT laminates by annealing in a magnetic field

A comprehensive investigation of magnetostriction optimization in Metglas 2605SA1 ribbons is performed to enhance magnetoelectric performance. We explore a range of annealing conditions to relieve remnant stress and align the magnetic domains in the Metglas, while minimizing unwanted crystallization. The magnetostriction coefficient, magnetoelectric coefficient, and magnetic domain alignment are correlated to optimize magnetoelectric performance. We report on direct magnetostriction observed by in-plane Doppler vibrometer and domain imagining using scanning electron microscopy with polarization analysis for a range of annealing conditions. We find that annealing in an oxygen-free environment at 400 °C for 30 min yields an optimal magnetoelectric coefficient, magnetostriction and magnetostriction coefficient. The optimized ribbons had a magnetostriction of 50.6 ± 0.2 microm m^-1 and magnetoelectric coefficient of 79.3 ± 1.5 microm m^-1 mT^-1. The optimized Metglas 2605SA1 ribbons and PZT-5A (d₃₁ mode) sensor achieves a magnetic noise floor of approximately 600 pT Hz^-1/2 at 100 Hz and a magnetoelectric coefficient of 6.1 ± 0.03 MV m^-1 T^-1.