Influence of Thermal Deformation on Exchange Bias in FeGa/IrMn Bilayers Grown on Flexible Polyvinylidene Fluoride Membranes

We investigated the influence of thermal deformation on the magnetic properties of flexible FeGa/IrMn exchange-biased (EB) bilayers grown on polyvinylidene fluoride (PVDF) membranes with the pinning direction parallel to the thermal deformation directions $\alpha _{31}$ and $\alpha _{32}$ of PVDF. Because with increasing temperature, the uniaxial anisotropy is reoriented from the $\alpha _{32}$ to $\alpha _{31}$ directions by the thermally induced compressive strain along the $\alpha _{32}$ direction, both the coercive field $H_{c}$ and the loop squareness $M_{r}/M_{s}$ of FeGa/IrMn bilayers display a complex temperature-dependent behavior. The EB field $H_{c}$ decreases with increasing temperature. A modified Stoner–Wohlfarth model was employed to account for the temperature dependence of magnetic properties in the flexible FeGa/IrMn bilayers.