Influence of samarium doping on structural, thermoelectrical properties of nanocrystalline cobalt ferrite

This study explores the impact of samarium (Sm³⁺) doping on the structural and thermoelectric properties of nanocrystalline cobalt ferrite (CoFe₂O₄). Samarium-substituted cobalt ferrite nanoparticles were synthesized through the citrate-gel auto-combustion method, followed by annealing at 500 °C for four hours. The investigation encompasses various analytical techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermoelectric power (TEP), and dielectric measurements. XRD analysis unveiled a distinctive single-phase cubic spinel structure in the ferrites. Notably, the lattice constant (a) and X-ray density (dx) demonstrated a discernible increase as the Sm³⁺ content rose, signifying significant structural modifications. SEM and TEM observations elucidated the morphology, revealing nanoparticles with a well-distributed yet occasionally agglomerated nature. TEP studies disclosed intriguing characteristics. The synthesized samples exhibited a discernible n-type semiconducting behavior, with the presence of transition temperatures that have been hitherto unreported. These transition temperatures have the potential to hold significance in thermoelectric applications. Furthermore, dielectric studies divulged intricate frequency-dependent behavior, offering insights into the dielectric parameters, such as εʹ, εʺ, Tanδ, and AC conductivity. This research contributes novel insights into the interplay between Sm³⁺ doping and the structural and thermoelectric properties of cobalt ferrite nanoparticles. The identification of hitherto unreported transition temperatures in the TEP measurements and the detailed analysis of dielectric behavior enhance our understanding of these promising materials, paving the way for innovative applications in thermoelectric devices and emerging technologies.