Mechanically tunable magnetic properties of Fe ₈₁Ga ₁₉ films grown on flexible substrates

We investigated on magnetic properties of magnetostrictive Fe ₈₁Ga ₁₉ films grown on flexible polyethylene terephthalate (PET) substrates under various mechanical strains. The unstrained Fe ₈₁Ga ₁₉ films exhibit a significant uniaxial magnetic anisotropy due to a residual stress in PET substrates. It was found that the squareness of hysteresis loops can be tuned by an application of strains, inward/compressive or outward/tensile bending of the films. A modified Stoner-Wohlfarth model with considering a distribution of easy axes in polycrystalline films was developed to account for the mechanically tunable magnetic properties in flexible Fe ₈₁Ga ₁₉ films. These results provide an alternative way to tune mechanically magnetic properties, which is particularly important for developing flexible magnetoelectronic devices.