Exploring the synergistic effects of La3+ substitution on dielectric performance of manganese cobalt ferrite: Implications for advanced electronic applications

Abstract

La3+ substituted Mn0.5Co0.5Fe2O4 ferrites were synthesized through sol-gel auto-combustion route. The impacts of varying doping concentrations (0.03, 0.06 and 0.09) were studied on synthesized samples' structural, optical, morphological, vibrational, and dielectric properties. The spinel cubic phase of synthesized samples was confirmed by X-ray diffraction (XRD) analysis; increased La3+ concentration has altered the structural parameters of prepared ferrites. Diffuse Reflectance Spectroscopy (DRS) shows a decrease in band gap with increasing concentration of La3+. Morphology has been reviewed by Field Effect Scanning Electron Microscope (FE-SEM), and elemental composition was confirmed by Energy Dispersive X-ray (EDAX) spectra. In addition, M − O stretching bonds were verified employing Fourier Transform Infrared (FTIR) spectroscopy. Raman Spectroscopy shows five modes, further confirming the spinel structure. The XPS spectra verified the +2 oxidation state of Manganese. Finally, the dielectric constant, tangent loss, and AC (Alternating Current) conductivity were analyzed with temperature at several frequencies. The experimental results have unveiled intriguing findings: the dielectric constant exhibited its maximum value at the lowest frequency within the investigated range, and it demonstrated an increasing trend with the rising temperature at a specific frequency. Notably, introducing La3+ through substitution has led to a noteworthy enhancement in the dielectric constant, underscoring the novel impact of this dopant on the material's electrical properties. A positive correlation existed between AC conductivity and temperature; as the temperature increases, so does the AC conductivity. Also, it was found to be maximum at maximum frequency value for all samples. Additionally, it can be deduced that raising the La3+ concentration in crystal improves the dielectric characteristics of Manganese Cobalt ferrites.