Influence of core-shell CoFe2O4-BaTiO3 and CoFe2O4-Bi4Ti3O12 on the magnetic properties

The current research is focused on the synthesis of non-magnetic shell layer on magnetic core CoFe2O4-X (X = BaTiO3 or Bi4Ti3O12), namely, CoFe2O4-BaTiO3 and CoFe2O4-Bi4Ti3O12 which were synthesized at different ratios by two-step wet chemical methods and characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDS), and Transmission Electron Microscopy (TEM). A Vibrating Sample Magnetometer (VSM) was used to examine the magnetic properties of samples influenced by particle size and morphology. All crystal phases were quantitatively determined by the XRD and refined by Rietveld method. After analyzing the results, it was seen that the nature of shell adhered on the core plays a crucial role in the controlling of core-shell formation impacting on the magnetic properties. The results show that the majority of the samples are presented in BaTiO3 in tetragonal, Bi4Ti3O12 in orthorhombic, and CoFe2O4 in cubic structures. The lattice distortions observed in the samples are associated with the shell dimentions, seeing that the ratio 50:50 was found to be suitable for the formation of superparamagnetic core-shell structure (shell size of ∼20 nm).