Exploring the supercapacitive potential of Sm3+doped CoFe2O4 nanoparticles: Enhanced magnetic and dielectric properties

This study investigates the impact of Sm3+ substitution on the structural, electrical, magnetic, and electrochemical properties of CoFe2O4 nanoparticles prepared via a combined solid-state reaction and mechanical milling approach. Rietveld refinement analysis confirms the presence of single-phase cubic spinel structures within the Fd3m space group for both CoFe2O4 (CF) and Co0.95Sm0.05Fe2O4 (SmCF). Field emission scanning electron microscopy and energy dispersive spectroscopy are employed to validate the microstructure and elemental composition. Tauc plot analysis reveals a decrease in the band gap from 2.24 eV for CF to 2.07 eV for SmCF. Hysteresis loop measurements demonstrate an enhancement in saturation magnetization, remanent magnetization, and magnetic moment for SmCF, indicating improved magnetic properties. Furthermore, a substantial increase in magneto -crystalline anisotropy is observed with Sm3+ doping. Frequency -dependent dielectric properties are investigated using Havriliak-Negami fitting, confirming the presence of Cole -Cole dispersion. A direct correlation between the dielectric constant and temperature is identified, suggesting higher temperatures lead to elevated values. Notably, the incorporation of Sm3+ results in a significant enhancement in specific capacitance, positioning SmCF as a promising candidate for energy storage applications, particularly in supercapacitors.