Soft X-ray absorption spectroscopy investigations of Bi6FeCoTi3O18 and LaBi5FeCoTi3O18 epitaxial thin films

High-quality single-crystalline Bi6FeCoTi3O18 and LaBi5FeCoTi3O18 thin films were prepared by pulsed laser deposition. X-ray diffraction characterizations indicate a more disordered lattice structure of the LaBi5FeCoTi3O18 film. The magnetic measurement results demonstrated significantly enhanced ferromagnetism in the LaBi5FeCoTi3O18 film. The modulation of oxidation and hybridization states caused by substituting Bi with La was studied using the soft X-ray absorption spectroscopy. The spectroscopic results revealed the reduced concentration of oxygen vacancies and the more distorted lattice structure in the LaBi5FeCoTi3O18 film, which explained the enhanced ferromagnetism. Published by AIP Publishing.