Hydrothermal Synthesis of Ce/Zr co-substituted BiFeO3: R3c-to-P4mm Phase Transition and Enhanced Room Temperature Ferromagnetism

Abstract

A facile hydrothermal method was used for fabricating phase-pure Bi1 − xCexFe1−xZrxO3 (x = 0.00, 0.03, 0.06) multiferroic ferrites, and the dependence of structural, optical, and magnetic properties on the composition have been investigated. The samples were investigated by X-ray diffraction (XRD), Raman and Fourier-transform infrared (FT-IR) spectroscopies, scanning electron microscopy, UV-Vis spectroscopy, and vibrating sample magnetometer at room temperature. Structural results show that the structure of Bi1 − xCexFe1−xZrxO3 ferrites is indexed to a rhombohedral structure with R3c space group. However, the weakening in the intensity, the expansion of the line-width of all bands, and some band shifts observed in Raman spectra indicate a structural transition from rhombohedral (R3c) to pseudo-tetragonal (P4mm) phase as the content of Ce/Zr increases. Also, a significantly enhanced intensity of the A1-2 mode in Raman spectra means that there is a novel behavior of magnetic anisotropy in the Ce/Zr co-substituted samples. A significant increase in optical band gap with increasing of the Ce/Zr co-substitution suggests that the materials are suitable for technological applications. Magnetic properties of the samples show a magnetic transition from antiferromagnetic to ferromagnetic phase due to the presence of the rhombohedral to the tetragonal phase transition, and exchange interaction between the 4f orbitals of the Ce3+/Ce4+ and the 3d orbitals of the Fe3+/Fe2+.