Herein, flexible polyvinylidenefluoride (PVDF) nanocomposite films reinforced with different concentrations of graphene nanoplatelets (GNPs), montmorillonite (MMT) nanoclay and titanium dioxide (TiO 2 ) nanoparticles (NPs) were prepared using a simple and low-cost solution casting method. The surface morphology of PVDF/GNPs/TiO 2 /MMT nanocomposites and the interaction between PVDF, GNPs, TiO 2 NPs and MMT nanofillers was examined using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) techniques. The dielectric properties of the prepared nanocomposite films were evaluated using a frequency response impedance analyzer in the frequency range from 50 Hz to 20 MHz at various temperatures. The electromagnetic interference (EMI) shielding effectiveness (SE) of PVDF/GNPs/TiO 2 /MMT nanocomposites was measured in the Ku-band region (12-18 GHz) and the maximum SE of 12.6 dB was obtained for nanocomposites with GNPs-2.5%, MMT-1% and TiO 2 -11.5%. Considering the excellent EMI shielding performance, these nanocomposites can have promising applications in smart electronics and flexible devices.

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The electronic, magnetic and optical properties of alkaline earth oxides XO (X = Ca, Sr, Ba) doped with 5d transition metal rhenium (Re) were investigated by applying first-principles calculations within the treatment of density functional theory based on a full potential linearised augmented plane wave method. 5d transition metal atom Re was doped to replace Ca/Sr/Ba atoms with 12.5% concentration to form the supercells. Density of states and band structures predict half-metallic characteristics of the supercells X0.875ORe0.125 (X = Ca, Sr, Ba). Half-metallic band gaps were observed clearly in the spin up majority channel around the Fermi level (EF). Dopant 5d transition metal atom Re creates a spin magnetic moment (μB) in the supercells X0.875ORe0.125 (X = Ca, Sr, Ba). Optical parameters (dielectric function ε(ω), absorption coefficient and reflectivity) were discussed. Materials exhibiting properties like absorption, reflectivity and half-metallic can be applicable for optoelectronics and spintronics devices.