Abstract
Y-type hexaferrite with nominal composition Ba2Co2Fe12O22 was synthesized by sol-gel method. The synthesized hexaferrite filler was mixed in 5 wt%, 15 wt% and 25 wt% respectively with Polyaniline (PANI) by insitu polymerization method to get hexaferrite-PANI composites. The synthesized samples were characterized by DC resistivity, XRD, VSM and dielectric measurements. The X-ray diffraction of polyaniline exhibit amorphous nature, whereas Ba(2)Co(2)Fe(12)O(22)exhibit single phase Y-type structure. Room temperature resistivity of the composites increased with increasing hexaferrite filler from 2.29 x 10(1) to 2.59 x 10(4) Omega-cm. Dielectric constant and complex dielectric constant measured in the frequency range of 1 Hz to 1 MHz. Both the real and imaginary parts of dielectric constant decreased with the increase of hexaferrite contents. AC conductivity was decreased with increasing Co2Y hexaferrite contents in PANI matrix and increased with increasing frequency following Maxwell-Wagner model. The saturation magnetization was observed to increase significantly with increasing hexaferrite filler, as it depends on volume fraction of magnetic particles and demagnetizing field produced by non-magnetic particles. Coercivity on average decreased with increasing hexaferrite filler which was due to the decrease in the inter particle distance and hence magneto static interactions enhanced amongst the particles. These composite materials are considered useful for applications of these materials in EMI shielding in low frequency range with added advantage of flexibility.