STRUCTURAL AND MAGNETIC CHARACTERIZATION OF POLYANILINE COMPOSITE FILMS

摘要

Abstract. In this work a novei approach for the preparation of Fe_3O_4/PANI (polyaniline) thin film composite containing magnetic nanoparticles is presented. Magnetite (Fe_3O_4) nanoparticles have been coated by PANI and the PANI chains have been doped by 10-camphorsulfonic acid (CSA). The doped composite is soluble in common organic solvents. Thin films of composites of polyaniline (PANI) were casted from m-cresol. Several characterization techniques were employed in order to determine composition, structure and magnetic properties of the nanocomposite film (X-ray diffraction, transmission electron microscopy, TEM, Scanning electron microscopy, SEM, and optical microscopy). The magnetization data were obtained from M(H) hysteresis loops and zero field cooling — field cooling, ZFC-FC. Magnetic measurements evidence a ferromagnetic behaviour of the obtained composite, at room temperature with saturation magnetization of about 3.4 emu/g and coercivity of 42 Oe. The temperature dependences of the conductivity of the films follows the σ(T) = σ_0 exp[ - (T_0/T)~(1/2) ] law, which has been explained within the framework of the one- dimensional variable-range-hoping (1D-VRH) model. Application of 1T magnetic field increases the resistivity of the film and the temperature slope dependence.