Structural, magnetic and dielectric properties of (PANI)-Ni0.5Zn0.5Fe1.5Cr0.5O4 nanocomposite

Polyaniline (PANI)-Ni0.5Zn0.5Fe1.5Cr0.5O4 (NZFCO) nanocomposites are conducting polymer-ferrite, which belongs to magneto-polymeric materials. They have very useful electromagnetic properties with new functions. The nanocomposites were synthesized in situ by polymerization of PANI in the presence of NZFCO nanoparticles. The results of XRD, FTIR spectra and TEM showed the presence of the two intended phases. The crystallite sizes measured were found to be in the nanorange (5-11 nm) which are almost in agreement with XRD data. The selected area electron diffraction (SAED) pattern of the nanocomposite, showed the superposition of both PANI ring and the single spot of the ferrite nano-crystallite {1 1 1} reflections, which confirms that PANI is covering the ferrite nanocrystallites. The DTA analysis indicated the high temperature stability of the nano-composite phase (347 degrees C) compared with PANI (270 degrees C). The highest magnetic saturation (Ms) was found for the nano-composite sample which have PANI concentration of (40% and 60%). The crystallite sizes, strains and change in lattice parameters were found to increase by increasing the percentage of PANI. The ac conductivity, dielectric constant and dielectric loss of all sample composition are much higher than that of PANI, the highest is for the sample which has has (60%) PANI concentration. The loss tangent were found to have very high values in the microwave range for certain concentrations and to have very low values for some other concentration with no definite systematic correlation. The temperature dependence of dielectric constant revealed a diffused phase transition (DPT) at higher temperature with higher dielectric constant of many order of magnitudes. The properties of magneto-polymeric nanocomposite are greatly influenced by the percentage of its component phases and the degree of mixing between the two phases. In general the different variety of the results obtained by just changing the relative percentage of PANI-NZFCO, made the present studied samples to be useful in many technological applications. (C) 2013 Elsevier Ltd. All rights reserved.