Structural, magnetic and optical properties of Al-substituted nickel ferrite nanoparticles

Aluminium (Al) substituted nickel ferrite (NiAlxFe2-xO4 with x = 0.0, 0.5 and 1.0) nanoparticles were synthesized by the technique of co-precipitation. The microstructural and optical properties of nickel ferrite nanoparticles were meticulously evaluated from X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and UV-vis spectroscopy. The X-ray diffraction pattern of nanoparticles confirmed the single phase of cubic spinel structure. The particle size of nickel ferrite nanoparticles was in the range of 25-35 nm, while the lattice parameter "a" decreased with respect to Al content. The presence of Ni, Fe, Al, and O elemental peaks in the energy dispersive X-ray spectrum confirmed the formation of nickel ferrite nanoparticles. The functional groups of Al-Ni spinel ferrite phase were further confirmed from Fourier transform infrared spectroscopy. Two major absorption bands in the IR spectrum were observed at 600 cm(-1) (the high frequency band, v(1)) and 450 cm(-1) (the low frequency band, v(2)) from tetrahedral (A) and octahedral (B) interstitial sites in the spinel lattice. The magnetic hysteresis curves were recorded with respect to Al concentration at room temperature using vibrating sample magnetometry. The magnetization and coercivity of nickel ferrite were decreased as the Al contents increased.