Latvijas Universitātes Cietvielu fizikas institūta, Doktorantūras skolas „Funkcionālie materiāli un nanotehnoloģijas”, Maģistra programmas B kursa „Aktuālas materiālu un cietvielu fizikas problēmas” zinātniskais seminārs 14. decembrī plkst. 13:00, LU CFI, Ķengaraga ielā 8, 2.stāva zālē Nobuo Nakajima (Hiroshima University) stāstīs par tēmu “Pre-edge features in the Ti K-edge XANES of perovskite titanates”.
Interpretations of pre-edge structures in the X-ray absorption spectra of 3d transition compounds have been in a long debate since the advent of synchrotron radiation sources: quadrupole (E2) or dipole (E1) transitions. Besides the origin of the optical process, the pre-edge structures contain various information related to material function. The dielectric properties of perovskite titanates are discussed quite often. We observed local ferroelectricity in SrTiO
3 under UV irradiation or by lattice distortion in thin films. Recently, we have succeeded to observe dynamic response of BaTiO
3 spectra to the applied electric field with time-resolved technique, and found that the pre-edge eg peak and the shoulder structure reflects different characteristics of dielectric properties.