Investigation of the Structure, Optical and Magnetic Properties of Bismuth-Doped Cobalt Ferrite

Abstract

The aim of this work was to investigate the structure, optical and magnetic properties of bismuth-doped cobalt ferrite nanoparticles (Co $$_{{1-x}}$$ BixFe2O4, x = 0, 0.05, 0.10) prepared by the sol-gel technique. X-ray diffraction indicated that the prepared samples were cubic spinel with space group Fd3m. The crystallite size, lattice parameter, and unit cell volume decreased with increasing bismuth ion content, which was explained by the difference in ionic radii. Magnetic measurements at room temperature using a vibrating-sample magnetometer showed a decrease in saturation magnetization, remanent magnetization, and coercive field from 76.92, 41.84 emu/g, 288.79 Oe to 34.62, 18.43 emu/g, 186.58 Oe, respectively, as the concentration decreased from x = 0 to 0.10. Spectroscopic measurements in the UV–visible region confirmed that the band gap increased from 2.252 to 2.321 eV as x increased from 0 to 0.10. The prepared samples were a semiconductor magnetic material and were used in a high magneto-optic recording device.