Effect of Sb doping on structural, electronic, and dielectric properties of Co3O4

Abstract

Cobalt-based oxides are promising candidates for advanced dielectric applications due to their versatile structural and electronic properties. In this work, we investigate the effect of antimony (Sb) doping on the structural and dielectric characteristics of Co₃O₄. A series of Sb-doped Co₃O₄ compounds was synthesized via solid-state reaction and characterized using X-ray diffraction, dielectric spectroscopy, and X-ray absorption techniques. X-ray diffraction analysis indicates that the solubility limit of Sb in Co₃O₄ is reached for dopant concentrations exceeding x = 0.3. Dielectric measurements reveal a significant increase in permittivity with temperature, accompanied by Maxwell-Wagner-type relaxation. X-ray absorption near-edge structure (XANES) analysis suggests that Sb incorporation modifies the local electronic environment due to the formation of oxygen vacancies, while extended X-ray absorption fine structure (EXAFS) results confirm the preservation of the Co₃O₄ framework with subtle changes in bond lengths and local disorder. Notably, Sb doping alters Co-O-Co bonding by inducing changes in bond distances. Overall, the dielectric response is strongly tuneable with Sb content, frequency, and temperature, highlighting the potential of Sb-doped Co₃O₄ for the design of functional dielectric materials.