Strain engineering for magnetoelectric coupling in flexible composite devices

This study explores strain-dependent regulation of magnetoelectric (ME) properties in flexible composite films. A flexible ME device with cylindrical assemblies of SmFe2 nanoclusters embedded in Bi5Ti3FeO15 matrix was prepared by low-energy cluster-beam deposition and wet chemical methods. Experimental results reveal distinct performance variations under different bending conditions. The strain-mediated magnetoelectric coefficient (αE31) exhibits a 29% enhancement under compressive stress due to improved mechanical strain transfer. However, in the tensile state, it marginally decreases due to depressed strain transfer. Using stress engineering, we achieve tunable and predictable strain-mediated αE31 regulation, with strain serving as a key control parameter. Furthermore, the flexible ME device maintains exceptional mechanical stability, with less than 7% variation in αE31 after 10 000 bending cycles. This work establishes a strain-mediated ME coupling strategy for flexible electronics, providing critical insights for wearable applications and adaptive strain sensors.