Improved structure stability, optical and magnetic properties of Ca and Ti co-substituted BiFeO3 nanoparticles
Abstract We report the optical and magnetic properties of single-crystalline Ca and Ti co-substituted bismuth ferrite, Bi 1-x Ca x Fe 1-x Ti x O 3 , nanoparticles, synthesized by a facile sol–gel methodology in the compositional range wherein 0 ≤ x ≤ 0.25. X-ray diffraction (XRD) and transmission electron microscopy (TEM) investigations show that all samples possess a rhombohedrally distorted perovskite structure with space group R3c. Ca and Ti co-substitution controls the formation of secondary phases and improved the stability of perovskite phase of BiFeO 3 . The average particle size was estimated by Williamson Hall plot, confirmed by TEM, and found to be about 59, 50, 46, 41, 40 and 38 nm of Bi 1-x Ca x Fe 1-x Ti x O 3 for x = 0, 0.05, 0.10, 0.15, 0.20 and 0.25, respectively. The UV–vis absorption study reveal the strong absorption of visible light with a small optical band gap (1.77–2.25 eV) for 0 ≤ x ≤ 0.25 indicates a possibility of utilizing for photocatalytic activities. The magnetic study at room-temperature displays the improved magnetization and coercive field in Bi 1-x Ca x Fe 1-x Ti x O 3 nanoparticles due to the release of the latent magnetization locked within the toroidal spin structure of BiFeO 3.