Structural and magnetic properties of CoFe2-x Gd (x) O-4 (0.0 a parts per thousand currency sign x a parts per thousand yen 0.1) spinel ferrite nanoparticles synthesized by starch-assisted sol-gel auto-combustion method

Abstract

In this present article, CoFe2-x Gd (x) O-4 (0.0 a parts per thousand currency sign x a parts per thousand yen 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) O-4 (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) O-4 nanoparticles were observed.