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Autori: I. Nicoara, M. Stef, A. Pruna
Editorial: Elsevier, Journal of Crystal Growth , 310, p.1470-1475, 2008.
Calcium fluoride crystals doped with YbF3 and PbF2-, NaF- and LiF-codoped were grown using the vertical Bridgman method. Transparent, high quality, with various high Yb2+ contents in the as-grown crystals has been obtained using a special procedure. The optical absorption spectra reveal the characteristic ultraviolet (UV) absorption bands of the divalent Yb ions. Influence of the codoping
with Pb2+, Li+ and Na+ ions on the absorption spectra and on the Yb2+ ions content has been studied. High-intensity emission bands in the near-UV spectral region, not reported before, have been observed for excitation by 230 nm. A comparison of our results with those obtained by other authors is also given.
Cuvinte cheie: Defecte, impuritiati, metoda Bridgman, compusi de calciu, compusi ai pamanturilor rare // Defects, directional solidification, impurities, Bridgman technique, calcium compounds, rare earth compounds