Synthesis, structural and high frequency dielectric properties of polypyrrole (PPy)/holmium ferrite composites

Conducting polymers and their composites are receiving considerable attention due to their applications in commercial and domestic appliances based on their electrical, optical and thermal properties. Also the magnetic and conducting properties of ferrite/polypyrrole (PPy) composites have opened a new horizon in multifunctional materials. In the present study, different properties of PPy, holmium substituted ferrite and their composites have been investigated. Prior to that, PPy was prepared by the chemical polymerization method of pyrrole in the presence of FeCl₃⋅6H₂O. Holmium substituted ferrite Co_0.02Ho_1.98Fe₂O₄ was prepared by using co-precipitation technique. The X-ray diffraction (XRD) pattern showed crystalline ferrite phase having an average crystallite size of 27 nm. Composites with different ratios of ferrite and PPy were fabricated using solid state reaction technique. The structural and morphological properties of PPy/Ferrite composites were studied by XRD and scanning electron microscopy (SEM), respectively. Frequency dependent dielectric properties were studied in the range of 1 MHz-3 GHz; the dielectric constant value for composite is higher than that for the holmium ferrite. The higher dielectric constant of the composite indicates that these materials have better ability to store potential energy under the influence of alternating electric field.