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

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.