Investigation of structural, microstructural and electrical characteristics of hydrothermally synthesized Li0.5-0.5xCoxFe2.5-0.5xO4, (0.0 <= x <= 0.4) ferrite nanoparticles

Lithium Ferrite is one of the fascinating materials because of its numerous applications in the electronic industry, defense, and environment. Herein, we report the synthesis of cobalt-doped Lithium nano ferrites (Li0.5-0.5xCoxFe2.5-0.5xO4, with x = 0.0, 0.1, 0.2, 0.3, 0.4) by employing the Hydrothermal approach. The X-Ray diffraction (XRD) pattern shows the formation of cubic spinel ferrite structure where crystallite size is observed to decrease from 86 nm to 44 nm whereas, lattice parameter increases from 8.354 angstrom to 8.397 angstrom with the increase in Co2+ ions concentration. The reduction in crystallite size is coupled to a rise in the lattice stain, which changes from 0.00131 to 0.00253 during the duration of the study. Rietveld refinement is performed to know the phase purity of prepared nanoferrites. Scanning electron microscopy (SEM) micrographs show the development of grains with irregular shapes and clearly visible grain boundaries. The grain size ranges from 210 to 702 nm. Complex Impedance Spectroscopy (CIS) shows the compositional dependence of Z' and Z'' with respect to frequency. The Cole-Cole plot shows the formation of single semi-circular arc that describes the dominance of grain. The electrical parameters from CIS plot show that the values of grain resistance (R-g), relaxation time (tau(g)) and grain conductivity (sigma g) ranges from 33.542 Omega to 17.459 Omega, 0.816 x 10(-4) s to 1.226 x 10(-4) s and 5.57 S/cm to 16.12 S/cm, respectively. The ac conductivity rises as the doping level rises, and the fact that there is a wide range of conductivity values show that all of the samples exhibit non-Debye behaviour.

Automated summary

In this study, cobalt-doped lithium ferrite nanoparticles were synthesized using the hydrothermal method. X-ray diffraction analysis confirmed the crystal structure and size changes, while scanning electron microscopy revealed the particle shape and boundaries. Complex impedance spectroscopy and electrical parameter analysis demonstrated the compositional dependence of conductivity and the impact of cobalt doping.