JOURNAL OF ALLOYS AND COMPOUNDS, cilt.509, ss.8460-8468, 2011 (SCI İndekslerine Giren Dergi)
Poly(3-pyrrol-1-ylpropanoic acid) (PPyAA)–Fe3O4 nanocomposite was successfully synthesized by an in situ polymerization of 1-(2-carboxyethyl) pyrrole in the presence of synthesized Fe3O4 nanoparticles. Evaluation of structural, morphological, electrical and magnetic properties of the nanocomposite was performed by XRD, FT-IR, TEM, TGA, magnetization and conductivity measurements, respectively. XRD analysis reveals the inorganic phase as Fe3O4 and TGA shows about 90 wt% loading of Fe3O4 in the nanocomposite. FT-IR analysis indicates a successful conjugation of Fe3O4 particles with polypyrrole acetic acid. Magnetization measurements show that polypyrrole acetic acid coating decreases the saturation magnetization of Fe3O4 significantly. This reduction has been explained by the pinning of the surface spins by the possible adsorption of non-magnetic ions during the polymerization process. The conductivity and dielectric permittivity measurements strongly depend on the thermally activated polarization mechanism and thermal transition of PPyAA in the nanocomposite structure. Large value of dielectric permittivity (?') of the nanocomposite at lower frequency is attributed to the predominance of species like Fe2+ ions and grain boundary defects (interfacial polarization).