Intrinsic Compositional Inhomogeneities in Bulk Ti-Doped BiFeO3: Microstructure Development and Multiferroic Properties
journal contributionposted on 14.05.2013, 00:00 by M. S. Bernardo, T. Jardiel, M. Peiteado, F. J. Mompean, M. Garcia-Hernandez, M. A. Garcia, M. Villegas, A. C. Caballero
Ti-doped BiFeO3 ceramics prepared by a mixed-oxide route were structurally characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM), giving evidence of the formation of an inner structure at the nanometric scale. The observed nanograins are separated by Ti-rich areas that originate due to the tendency of the titanium dopant to segregate from the perovskite lattice. Such a peculiar nanostructure is responsible for the changes produced in both the electrical and the magnetic properties of BiFeO3 upon titanium doping: the Ti-rich interfaces act as resistive layers that increase the direct-current (dc) resistivity of the material, while the existence of structural domains in the scale of tens of nanometers causes a ferrimagnetic-like behavior with a huge coercive field (on the order of 20 kOe), even at room temperature.