Comparison of room-temperature multiferroics in Bi4Fe2TiO12 film and bulk

It was reported that both dielectricity and magnetism at room temperature were appreciably improved in Bi₄Fe₂TiO₁₂ film compared with Bi₄Fe₂TiO₁₂ bulk. X-ray diffraction profiles reveal similar crystalline nature and random orientation of the two, but X-ray photoelectron spectroscopy (XPS) experiments indicate that it is 1.4 eV lower binding energy of core-state O1s in the film relative to that of the bulk, so the improvement of multiferroics in the film is attributed to oxygen vacancies and high fraction of interface. The results have promising applications in multifunctional integrated devices.