Structural and optical absorption studies of cobalt substituted strontium ferrites, SrCo_xFe_12−xO₁₉ (x = 0.1, 0.2 and 0.3)

Abstract

Cobalt substituted strontium ferrites SrCo_xFe_12−xO₁₉ (x = 0.1, 0.2 and 0.3) were synthesized via sol–gel method and the dried gel obtained was annealed at 800 °C. The powder X-ray diffraction studies helped in the determination of the crystallite size that measured ≈ 12–14 nm. The optical properties of the powdered nanoparticles were determined by means of the UV–Vis absorption spectra of their dispersed solutions in liquid media. Despite these measurements, it was difficult to determine their band gap (E_g) precisely. However, the Kubelka–Munk treatment on the diffuse reflectance spectra of the powdered nanoparticles was used in order to extract their E_g unambiguously. The Co substituted strontium hexaferrites are used for optical studies. The energy band gap for all the ferrite compositions was found to be ≈ 1.46–1.78 eV. The study made on the dielectric behaviour of the substituted SrFe₁₂O₁₉ is also discussed in this paper.