Ni–Ag ferrites synthesized by sol gel route using aloe vera extract as a solvent: Enhancement in structural, dielectric, magnetic and optical properties

Abstract

The Ag+ doped nanocrystalline nickel ferrites, NiAgxFe2-xO4 (NAF) with x = 0–0.1 were synthesized by sol gel route using aloe vera extract as a solvent. The analysis of X-ray diffractogram reveals the creation of spinel phase within the pristine Ni ferrite. The phase of nano Ag particles coexists along with the spinel phase for doped NAF, which was confirmed by the Rietveld refinement of XRD patterns. The wt. % of metallic nano Ag and spinel phase was calculated from the refined XRD data. The mean size of the ferrite crystallites calculated from Debye-Scherer method was 44 nm. The TEM analysis confirms the nanocrystalline nature of the ferrites. The SAED image of the ferrite confirms the creation of spinel phase within the ferrite. The morphological analysis by SEM explores the layered arrangement of spherical nanoparticles within the NAF crystals. The EDS analysis shows the absence of impurity elements in the synthesized ferrites. The dielectric constant and loss tangent were studied as a function of frequency and Ag+ composition. The analysis of hysteresis loops depicts the soft magnetic behavior of the NAF samples. The optical properties of NAF crystals were studied from the UV Vis absorption spectra within the wavelength range 400–800 nm. The band gap energies were decreased with the increasing Ag+ composition due to the contribution of delocalized electrons in direct optical transitions.