Magnetoelastic coupling effect of Fe₁₀Co₉₀films grown on different flexible substrates

The magneto-mechanical coupling effect and magnetic anisotropy of Fe10Co90 (FeCo) films deposited on silicon wafer (Si), flexible polyethylene terephthalate (PET), freestanding polydimethylsiloxane (PDMS), and pre-stretched 20% PDMS substrates were studied in detail. The loop squareness ratio M r/M s and the coercive H c of the FeCo film grown on a PET substrate can be obviously tuned by applying a small tensile-bending strain, and those of the FeCo film grown on a freestanding PDMS substrate can only be slightly changed when applying a relatively large tensile bending strain. For the FeCo film prepared on a 20% pre-stretched PDMS, a wrinkled morphology is obtained after removing the pre-strain. The wrinkled FeCo film can keep the magnetic properties unchanged when applying a relatively large tensile bending strain perpendicular to the wrinkles. This reveals that PDMS is an ideal substrate for magnetic films to realize flexible immutability. Our results may help for developing flexible magnetic devices.