Mechanically tunable magnetic properties of Fe81Ga19 films grown on flexible substrates
Date: 2014-04-05, Hits: 473

We investigated on magnetic properties of magnetostrictive Fe81Ga19 films grown on flexible polyethylene terephthalate (PET) substrates under various mechanical strains. The unstrained Fe81Ga19 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 Fe81Ga19 films. These results provide an alternative way to tune mechanically magnetic properties, which is particularly important for developing flexible magnetoelectronic devices.

The authors acknowledge the financial support from the National Natural Foundation of China (11174302), State Key Project of Fundamental Research of China (2012CB933004), Zhejiang and Ningbo Natural Science Foundations, Chinese Academy of Sciences (CAS), and Ningbo Science and Technology Innovation Team (2011B82004, 2009B21005).

(a) Summary for the strain dependence of squareness with the magnetic field applied along the easy and hard axes. (b) Calculated squareness of hysteresis loops as a function of the strain-induced uniaxial anisotropy Ke/Ms using the Stoner-Wohlfarth model (dashed lines) and our modified one (solid lines with symbols). Calculated hysteresis loops under various Ke/Ms for the magnetic field