Synthesize, characterization, dielectric, linear and nonlinear optical properties of Ni–Al Ferrite/PANI nanocomposite film

Abstract

In this work, NiAl-ferrite/PANI/x (PANI) Nano composite Films (x = 0.2, 0.4, 0.6 and 0.8) were prepared using a solution casting process. Films were synthesized to achieve a good magnetic property of polymer and add more conductive properties to NiAl x Fe 2-x O 4 . The NiAl x Fe 2-x O 4 nanoparticles are synthesized by flash auto combustion method, and PANI is synthesized by situ-chemical oxidative polymerization method. Characterization was carried out by XRD, FTIR, TGA, TEM, EDAX, SEM, and UV–vis to investigate thermal, dielectric and linear -nonlinear optical properties of nanocomposite films. The average crystallite size was calculated using and Williamson - Hall (W–H) method. The FTIR spectra confirm the incorporation of nano ferrite particles in polyaniline matrix. The SEM and TEM images show that, the NiAl x Fe 2-x O 4 particles are highly agglomerated in granular-like morphology and have spherical coral-like particles embedded in the PANI matrix in a core–shell structure. From TGA curves, the average activation energy of three main stages of weight loss of decomposition are 37.93, 50.91 and 55.36 kJ/mol. The optical energy gap E g value decreases from 4.47 to 4.07 eV and 4.24 to 3.84 eV for direct and indirect transitions with increasing Al content. The refractive index and real part of dielectric values are high in the UV region, while the extinction coefficient, imaginary part of dielectric and the dielectric loss tangent are high in the visible region and near-infrared region. The optical conductivity values increase slightly with increasing UV photon energy, rapidly grows above 4 eV. Non-uniform changes are noticed in the values of dispersion energy, E d , and the single oscillator energy, E o , and the values of linear optical constants ( λ o , n ∞ , S o , ε ∞ and (e 2 /πc 2 ) (N/m*) ). The nonlinear optical constants including third order nonlinear optical susceptibility χ ( 1 ) , χ ( 3 ) and reflective index n 2 were calculated. The values of χ ( 3 ) and n 2 were around ≈ 10 − 11 ( e s u ) a n d ≈ 10 − 10 , respectively. • Solution casting process was used to synthesis NiAl-ferrite/PANI nanocomposite films. • From FTIR spectra, formation of spinel ferrite and the incorporation of nano ferrite particles in PANI matrix have been confirmed. • Increasing the Al content in the ferrite, changed the surface morphology of PANI to a more complicated shape, and increased the accumulation. • In the TGA analysis, the average values of activation energy of degradation are 37.93, 50.91, and 55.36 KJ/mol , respectively. • The optical conductivity values increase slightly with increasing UV photon energy, rapidly grows above 4 eV.