Study of structural, optical and electrical properties of La3+doped Mg0.25 Ni0.15 Cu0.25 Co0.35 Fe2-x Lax O4 spinel ferrites

Lanthanum substituted Mg-Ni-Cu-Co ferrite nanoparticles prepared through the Sol-Gel method were studied using different methods such as XRD, FTIR, UV-VIS, SEM, Raman, LCR, EDX and IV to evaluate the structural, optical and electrical properties. The single-phase cubic spinel structure of the prepared samples was confirmed from X-ray diffraction analysis. The FT-IR spectra indicated two absorption bands, nu(1) and nu(2) that represent the complex Fe3+-O2- at A-site (tetrahedral) and B-site (octahedral) vibration. The optical band gap decreased from 2.48eV to 1.53eV observed by UV-Vis, and matched with the electrical resistivity measurements. Variation in the lattice parameters from XRD, the absorption band (octahedral) from FTIR, the optical energy band gap from the UV-vis data and the DC resistivity demonstrated change in structural, optical and electric properties of Mg-Ni-Cu-Co ferrites nanoparticles due to the addition of the rare earth element La3+. Both the dielectric losses and dielectric constant of the prepared samples decreased due to the La3+ ions doping, and A.C conductivity increased with increasing the value of frequency from 8 Hz to 8 M Hz. The variation in Raman peaks reveals that Raman shift varied due to the La3+ addition. EDX data confirmed the stoichiometric calculations of La(3+)ions substituted into Mg-Ni-Cu-Co ferrite nanoparticles.