Tailoring the Effect of La3+ Substitution on Structural, Magnetic and Optical Properties of Ba0.7Co0.3LaxFe2-xO4

Abstract Ba0.7Co0.3LaxFe2-xO4 nano spinel ferrites, with lanthanum substitution, were synthesized using the sol-gel auto-combustion technique. Various techniques, including Crystallographic X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), high-resolution scanning electron microscopy (HRSEM), vibrating sample magnetometer (VSM), and UV-vis spectroscopy, were used to study their structural, morphological, magnetic, and optical parameters. The XRD patterns indicated the formation of a single-phase nanocrystalline structure, with an increase in lattice constant due to Lanthanum substitution. FTIR spectrum confirmed the presence of the M-O stretching band and facilitated a study of functional groups. HRSEM images exhibited the formation of uniform, cubic, spherical nanoparticles with gentle agglomerations. The VSM study highlighted alterations in saturation magnetizationMS, remanenceMR, coercivityHC, and Y-K angles, indicative of the impact of La3+ ions. UV-visible spectroscopy determined an increase in the bandgapEg, suggesting potential applications of synthesized nano-ferrites in various fields like optoelectronics and non-linear optical filter devices. Structural parameters, such as X-ray density, dislocation density, X-ray morphology index, distortion parameter, and interchange distance, were also measured based on the XRD data. These lower Eg, HC, and Mr values suggest potential applications of synthesized nano-ferrites in optical domains, photo-catalysis water splitting, optoelectronics, and non-linear optical filter devices.