Study of structural, electrical, optical and magnetic properties of Hexaferrite-Polyaniline nanocomposites

Y-type hexagonal ferrite (CaBaCo2Ca0.5Fe11.5O22) was synthesized by sol-gel technique. The ferrite-polymer composites (1 = x)CaBaCo2Ca0.5Fe11.5O22 + (x)polyaniline (x = 0.25, 0.50, 0.75, 1) namely PF1, PF2, PF3 and polyaniline (PANI) were synthesized by in situ polymerization. The synthesized samples were characterized by XRD, SEM, electrical and dielectric measurements, optical and magnetic studies. XRD pattern reveals a broad peak of polyaniline which is an indication of amorphous nature of PANI. Room-temperature resistivity increases from 2.14 x 10(1) Omega.cm to 2.78 x 10(10) Omega.cm as ferrite content increases due to resistive behavior of the ferrite particles dispersed in the PANI matrix. The value of dielectric constant decreases at fixed frequency with increasing concentration of ferrite filler which is predominantly due to exchange of electrons between Fe+2 and Fe+3 ions that ultimately results in enhancement of electric polarization and conductivity. The optical bandgap increases with increasing amount of ferrite in the composites. The saturation magnetization and remanence increase with the increase of ferrite filler amount in PANI matrix whereas coercivity decreases. The decrease in coercivity and increase in saturation magnetization are related to Brown's relation. The present nanocomposite samples may be the best candidates for electromagnetic shielding.