Ferroelectric phase transition in polycrystalline KTaO.sub.3./sub. thin film revealed by terahertz spectroscopy

0373954 - FZÚ 2012 RIV US eng J - Journal Article
Skoromets, Volodymyr - Glinšek, S. - Bovtun, Viktor - Kempa, Martin - Petzelt, Jan - Kamba, Stanislav - Malič, B. - Kosec, M. - Kužel, Petr
Ferroelectric phase transition in polycrystalline KTaO₃ thin film revealed by terahertz spectroscopy.
Applied Physics Letters. Roč. 99, č. 5 (2011), 052908/1-052908/3. ISSN 0003-6951. E-ISSN 1077-3118
R&D Projects: GA ČR GD202/09/H041; GA AV ČR(CZ) IAA100100907
Grant - others:GAUK(CZ) SVV-2011-263303
Institutional research plan: CEZ:AV0Z10100520
Keywords : thin film * terahertz spectroscopy * ferroelectric phase transition
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 3.844, year: 2011
http://link.aip.org/link/?APL/99/052908

KTaO3 single crystal is an archetypal incipient ferroelectric in which a long-range ferroelectric order does not establish at low temperatures owing to quantum fluctuations. We report on a strong evidence of the ferroelectric phase transition near 60 K revealed by terahertz spectroscopy and microwave permittivity measurements of a polycrystalline KTaO3 thin film on (0001) sapphire substrate prepared by chemical solution deposition. The soft mode behavior is clearly observed in the terahertz (THz) spectra with a minimum frequency at 60 K. At the same temperature microwave permittivity maximum appears. The THz spectra strongly resemble that of strained epitaxial SrTiO3/DyScO3 films: the ferroelectric soft mode is linearly coupled to a central peak which is silent in the paraelectric phase and it becomes coupled to the polarization below the ferroelectric transition temperature with a progressively increasing bare strength.
Permanent Link: http://hdl.handle.net/11104/0206990