Investigation of Crystallographic, Morphological, Magnetic and Electrochemical Properties of La-Doped Cu-CoFe2O4 Spinel Ferrites

This research presents the successful synthesis of Cu_0.79Co_0.21La_xFe_2-xO₄ (0.0 ≤ x ≤ 0.8) (spinel ferrite) nanoparticles via the sol-gel auto combustion technique, with varying La³⁺ dopant concentrations. In this study, the estimated crystallite size (D) is found to be in the range of (27.92–40.90) nm. The microstructural parameter determination in XRD data is improved using Rietveld refinement. Fourier Transform Infrared Spectroscopy (FTIR) spectra exhibit two distinct metal stretching vibrational bands within (400–600) cm⁻¹ range, a characteristic fingerprint region for all ferrites. Field Emission Scanning Electron Microscopy (FESEM) analysis reveals the agglomeration of particles due to magnetic interactions and non-uniform distribution of average particle sizes ranging from (1.06–1.87) µm. Energy Dispersive X-Ray Analysis (EDX) validates the chemical composition's accuracy. Owing to the dilution effect resulting from the introduction of non-magnetic La³⁺ ions into the ferrite structure, there is a reduction in the saturation magnetization value, decreasing from 37.28 to 6.24 emu g⁻¹ in the Vibrating Sample Magnetometery (VSM) study. The electrochemical analysis reveals the impressive electrochemical characteristics of the newly developed ferrites, highlighting a remarkable specific capacitance of 270.0 F g⁻¹. This finding positions them as highly promising contenders for a wide range of energy storage supercapacitor applications.