Thermally assisted electric field control of magnetism in flexible multiferroic heterostructures

Thermal and electrical control of magnetic anisotropy were investigated in flexible Fe₈₁Ga₁₉ (FeGa)/Polyvinylidene fluoride (PVDF) multiferroic heterostructures. Due to the large anisotropic thermal deformation of PVDF (α₁= -13 × 10^-6 K^-1 and α₂= 145 × 10^-6 K^-1), the in-plane uniaxial magnetic anisotropy (UMA) of FeGa can be reoriented 90° by changing the temperature across 295 K where the films are magnetically isotropic. Thus, the magnetization of FeGa can be reversed by the thermal cycling between 280 and 320 K under a constant magnetic field lower than coercivity. Moreover, under the assistance of thermal deformation with slightly heating the samples to the critical temperature, the electric field of ± 267 kV cm^-1 can well align the UMA along the two orthogonal directions. The new route of combining thermal and electrical control of magnetic properties realized in PVDF-based flexible multiferroic materials shows good prospects in application of flexible thermal spintronic devices and flexible microwave magnetic materials.