We have investigated domain structures in Bi4Ti 3O12 (BiT) single crystals by Raman scattering using scanning near-field optical microscopy (SNOM). In SNOM-Raman spectra, the polarization dependence reflects domain structures, and the spectra at the domain-wall region exhibit the splitting of the TiO6 mode at ∼840 cm-1 with the appearance of additional peaks, the behavior of which is different from that observed in the single-domain region. From the resonant Raman spectra of highly deficient BiT single crystals, we find that the resonance is localized at oxygen vacancies in TiO6 octahedra, and planer defects, owing to oxygen vacancies, accumulate near the domain walls, causing a strong domain pinning.
ASJC Scopus subject areas
- Physics and Astronomy(all)