Luminescence and possible phase transformations in Cr-doped SrTiO3and Sr0.998Ca0.002TiO3thin films deposited by the excimer laser ablation method

Autor:	V. Trtík, F. Smutný, T. A. Shaplygina, V. S. Vikhnin, Z. Potůček, Miroslav Jelinek, Maxim Savinov, V. A. Trepakov, Lubomir Jastrabik, Z. Bryknar
Rok vydání:	1996
Předmět:	Materials science Photoluminescence business.industry Analytical chemistry Condensed Matter Physics Ferroelectricity Electronic Optical and Magnetic Materials Blueshift Optics Excited state Phase (matter) Thin film Luminescence business Saturation (magnetic)
Zdroj:	Ferroelectrics. 184:41-49
ISSN:	1563-5112 0015-0193
DOI:	10.1080/00150199608230243
Popis:	The dielectric permittivity and photoluminescence of the title films were studied in detail. SrTiO3:Cr films show a temperature maximum of e′ (T) and a saturation of the TO-mode softening near 100 K. In (SrCa)TiO3:Cr films a temperature maximum of e′ occurs at 28 K; we suggest this is due to an onset of XY, n = 2 quantum ferroelectricity. A ‘blue shift’ of the zerophonon R-luminescence line of octahedral Cr3+ in SrTiO3 films, and an increase of vibronic sideband intensities in comparison with Cr3+ luminescence in the same crystals are reported and discussed. Attention was focussed on SrTiO3:Cr films in order to explain a large and unusual temperature shift of the R-luminescence line position. It is shown that this shift is a consequence of local configurational instability and the off-center position of Cr3+ in the ground 4A2-state and the excited 2E-state, which occurs at least for T < 77 K.
Databáze:	OpenAIRE
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