Local structure studies of SrTi.sup.16./sup.O.sub.3./sub. and SrTi.sup.18./sup.O.sub.3./sub

0441459 - FZÚ 2015 RIV GB eng J - Článek v odborném periodiku
Anspoks, A. - Bocharov, D. - Purans, J. - Rocca, F. - Sarakovskis, A. - Trepakov, Vladimír - Dejneka, Alexandr - Itoh, M.
Local structure studies of SrTi¹⁶O₃ and SrTi¹⁸O₃
Physica Scripta. Roč. 89, č. 4 (2014), "044002-1"-"044002-5". ISSN 0031-8949. E-ISSN 1402-4896
Grant CEP: GA ČR GAP108/12/1941
Institucionální podpora: RVO:68378271
Klíčová slova: near-edge structure * K phase-transition * soft phonon modes * strontium-titanate
Kód oboru RIV: BM - Fyzika pevných látek a magnetismus
Impakt faktor: 1.126, rok: 2014

In this work we report on the local structure of Ti in (SrTiO3)-O-16 (STO16) and (SrTiO3)-O-18 (STO18) investigated in the low temperature range (6-300 K) by extended x-ray absorption fine structure and x-ray absorption near edge structure (XANES) spectroscopy at Ti K-edge and by optical second harmonic generation (SHG). By comparing XANES of STO16 and STO18 we have identified the isotopic effect which produces at T < 100K a noticeable difference in the measured mean square relative displacements (MSRD) of Ti-O-1 bonds: while STO16 follow the expected Einstein-like behavior, for STO18 we have measured an increase of MSRD values with decreasing temperature. This is an indication of an increasing off-center position of the Ti atoms in the TiO6 octahedra.
Trvalý link: http://hdl.handle.net/11104/0244450