Magnetic and dielectric properties of barium ferrite fibers/poly(vinylidene fluoride) composite films

Barium ferrite fibers/poly(vinylidene fluoride) (BaFe12O19/PVDF) composite films were prepared from poly(vinylidene fluoride) (PVDF) resin with different weight percentages (1, 5, 10, 20, 30 wt%) of M-type barium ferrite fibers using N,N-dimethylformamide as a solvent. The structure and morphology of the BaFe12O19/PVDF composite films were characterized by scanning electron microscopy and X-ray diffraction. These results show that BaFe12O19 fibers with diameters around 1 mu m and an aspect ratio (length/diameter) of about 50 are well dispersed in the PVDF resin and the dispersed fibers result in a structural change of the PVDF from alpha to beta phase. Measurements of the magnetization of the composite films by using a vibrating sample magnetometer show that these BaFe12O19/PVDF composite films possess a hard magnetic characteristic. The specific saturation magnetization and dielectric loss increase with BaFe12O19 content, whereas the coercivity and dielectric constant of the composite films are less affected. These BaFe12O19/PVDF composite films can combine magnetic, dielectric, and mechanical properties of the BaFe12O19 and PVDF phases.