Structural and Magnetic Properties of CoFe2−x Gd x O4 (0.0 ≤ x ≥ 0.1) Spinel Ferrite Nanoparticles Synthesized by Starch-Assisted Sol–Gel Auto-combustion Method

Abstract

In this present article, CoFe2−x Gd x O4 (0.0 ≤ x ≥ 0.1) nanoparticles were synthesized by starch-assisted sol–gel auto-combustion method. Powder X-ray diffraction patterns revealed the formation of cubic spinel ferrite with the signature of GdFeO3 phase at higher Gd3+ concentration. The field emission scanning electron microscopy study demonstrated the spherical nanoparticle in the size range 4–10 nm. Raman and Fourier transform infrared spectra supported the formation of the spinel ferrite structure in the nanocrystalline form. The X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of Co2+ and Fe3+ at the octahedral site as well as the tetrahedral site in CoFe2−x Gd x O4 (x = 0.05) nanoparticles. The distribution of Fe3+ ions was obtained to be about 73 % in the octahedral sites and about 27 % in the tetrahedral sites. The distribution of Co2+ ions at the octahedral and tetrahedral sites were 78 and 22 %, respectively. The increase in saturation magnetization and coercivity from 14.59 emu/g (x = 0.00) to 16.11 emu/g (x = 0.025) and 51.75 Oe (x = 0.00) to 92.86 Oe (x = 0.050), respectively, in CoFe2−x Gd x O4 nanoparticles were observed.