Abstract
Nanocrystalline nickel ferrite (NiFe2O4) powder of crystallite size ~20 nm was synthesized by refluxing method. Electrically conductive polyaniline-nickel ferrite (PANI/NiFe2O4) nanocomposites have been synthesized by an in-situ polymerization of aniline monomer in the presence of as-prepared NiFe2O4 in different weight percentage (5%, 10%, and 15%). These nanocomposites were subsequently characterized for morphological, crystalline, structural, electrical and magnetic properties by Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Four Probe Resistivity (FPR) and Vibrating Sample Magnetometer (VSM). Existence of NiFe2O4 in the nanocomposites was confirmed by XRD, FTIR and TEM analysis. The change in morphology with crystallite size ? 50 nm was observed for the nanocomposites clearly indicate the coating of PANI on NiFe2O4 . Nanocomposites showed increase in saturation magnetization as compared to that of PANI and increase in electrical conductivity as compared to that of NiFe2O4 indicating the synergistic effect of individual components. The saturation magnetization drastically increased as nickel ferrite content changed from 5 to 15% in nanocomposites. The conductivity of nanocomposites increased with temperature, exhibiting typical semiconductor behavior. The nanocomposites show semiconducting and ferromagnetic behaviour. The electrical conductivity of nanocomposites decreased from 1.089 to 0.268 S/cm, but saturation magnetization increased from 0.97 to 2.803 emu/g, when ferrite content changed from 5 to 15 wt%, indicates such nanocomposites are good for electromagnetic devices.
Highlights
Conducting polymers have been studied extensively due to their intriguing electronic and redox properties and numerous potential applications in many fields since their discovery in 1970s [1]
We have reported the effect of nanocrystalline nickel ferrite (NiFe2O4) on electrical and magnetic properties of polyaniline nanocomposites in order to find the application of such multifunctional composites in electromagnetic devices
PANI/NiFe2O4 nanocomposites have been characterized by X-Ray Diffraction (XRD) (Philips PW 1730 automatic X-ray diffractometer with Cu-Ka radiation of =1.5428 ̊A), Transmission Electron Microscopy (TEM) (Hitachi H-7000 operated at 100 kV and 30 A), Magnetic measurement using EG & G PAR model 4500 vibrating sample magnetometer and electrical resistivity measurement using four point probe technique was done to study the effect of nanocrystalline nickel ferrite on the electrical and magnetic properties of polyaniline
Summary
Conducting polymers have been studied extensively due to their intriguing electronic and redox properties and numerous potential applications in many fields since their discovery in 1970s [1]. Among the various conducting polymers synthesized, polyaniline (PANI) occupies a prime position, because of its unique characteristics like inexpensiveness of the monomer, ease of processing and excellent stability. PANI in its pure and doped forms find extensive applications in making devices like polymer light emitting diodes, photovoltaics, sensors, batteries and super capacitors [5]. The relative content of the benzoid and quinoid forms in PANI depends on the acid concentration and the degree of oxidation of the polymer [6]. It can be protonated by aqueous acid with increase in conductivity of almost 10 orders of magnitude, forming a polysemiquinone radical which contains a delocalized half-filled broad polaron energy band
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