Correlation between Luminescence and EPR Spectroscopy as Evidence of Ytterbium Pair Formation in Li6Ln(BO3)3:Yb3+ (Ln=Gd,Y) Borate Single Crystals |
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| Authors: | Dr Véronique Jubera Dr Marie Chavoutier Dr Alla Artemenko Dr Philippe Veber Dr Matias Velazquez Dr Alain Garcia |
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| Institution: | 1. Optical Materials, CNRS, Université de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, Pessac, F‐33608 (France), Fax: (+33)?5?4000?2761;2. Institute for Problems of Material Science, NASc of Ukraine, 3 Krjijanovskogo Str., 03680 Kiev‐142 (Ukraine) |
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| Abstract: | Synthesized powders and grown single crystals of nominal compositions Li6Ln(BO3)3:Yb3+ (Ln=Y, Gd) were investigated by means of powder and single‐crystal X‐ray diffraction (XRD), as well as optical near‐IR spectroscopy in conjunction with electron paramagnetic resonance (EPR) spectroscopy. The appearance of two distinct zero‐phonon lines suggests the existence of two kinds of Yb3+ ions in the single crystals. The XRD results exclude the possibility of a phase transition occurring between room and low temperatures. EPR spectra of single crystals show the presence of both isolated ions and pairs of ytterbium ions substituted for Y3+. A strong temperature dependence of the intensity of Yb–Yb pairs resonance lines coincides with temperature dependence of emission peak at 978 nm, confirming a common origin of the defect giving rise to these spectra. Calculated from EPR spectra, the distance between pairs of Yb3+ is in good agreement with crystallographic ones: R=3.856 Å, Rcryst=3.849 Å. |
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| Keywords: | crystal growth epr spectroscopy luminescence X‐ray diffraction ytterbium |
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