Highly magneto-electric-mechanical coupling effect in self-biased magnetoelectric composite induced by laser thermal annealing.

The development of advanced magnetoelectric (ME) composites necessitates high-performance materials that are capable of achieving high levels of ME coupling, minimal magnetic loss, and absence or limited reliance on external excitation sources. In this paper, a (2-2) connectivity ME laminate integrates multiple layers of FeSiB alloy (Metglas) and Pb (Mg, Nb) O₃-PbTiO₃ (PMN-PT) single crystal, achieving a remarkable ME coupling coefficient of 2033.4 V/Oe·cm (sevenfold rise) by laser thermal annealing treatment. Here, the laser-induced nanostructures on Metglas, with an oxidized insulation layer and soft and hard magnetic dipole layer improve the Magneto-electric-mechanical coupling with a mechanical quality factor (Q_m) exceeding 350. More importantly, the interaction between amorphous and nanocrystalline dipoles triggers an Exchange Bias (EB) effect, leading to a self-biasing performance of 67.45 V/Oe·cm. Furthermore, the composite exhibits an excellent passive DC magnetic detection limit of 22 nT, and an improved weak AC magnetic detection limit down to 383 fT. These explorations offer the potential to enhance passive current measurement, and underwater communication, extend weak magnetic positioning and brain magnetic detection.