Influence of Bi3+-doping on the magnetic and Mössbauer properties of spinel cobalt ferrite

Abstract

The influence of Bi3+-doping on the magnetic and Mössbauer properties of cobalt ferrite (CoFe2O4), wherein the Fe3+ ions are replaced by the Bi3+ ions to form CoBixFe2-xO4 ferrites, where x = 0.0, 0.05, 0.1, 0.15 or 0.2, has been investigated. The structural and morphological properties of undoped and doped ferrites, synthesized chemically through a self-igniting sol-gel method, are initially screened using X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy measurements. The changes in magnetic moment of ions, their coupling with neighboring ions and cation exchange interactions are confirmed from the Mössbauer spectroscopy analysis. The effect of Bi3+-doping on the magnetic properties of CoFe2O4 ferrite is examined from the vibrating sample magnetometry spectra. Saturation magnetization and coercivity values are increased initially and then decreased, as result of Bi3+-doping. The obtained results with improved saturation magnetization (from 26.36 to 44.96 emu g-1), coercivity (from 1457 to 1863 Oe) and remanence magnetization (from 14.48 to 24.63 emu g-1) on 0.1-0.15 mol Bi3+-doping of CoBixFe2-xO4 demonstrate the usefulness for magnetic recording and memory devices. This journal is