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Correlation between Luminescence and EPR Spectroscopy as Evidence of Ytterbium Pair Formation in Li 6 Ln(BO 3 ) 3 :Yb 3+ (Ln=Gd, Y) Borate Single Crystals
Author(s) -
Jubera Véronique,
Chavoutier Marie,
Artemenko Alla,
Veber Philippe,
Velazquez Matias,
Garcia Alain
Publication year - 2011
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201100059
Subject(s) - electron paramagnetic resonance , ytterbium , spectroscopy , ion , luminescence , single crystal , spectral line , crystallography , analytical chemistry (journal) , chemistry , resonance (particle physics) , materials science , nuclear magnetic resonance , doping , atomic physics , physics , optoelectronics , organic chemistry , quantum mechanics , astronomy , chromatography
Synthesized powders and grown single crystals of nominal compositions Li 6 Ln(BO 3 ) 3 :Yb 3+ (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 Yb 3+ 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 Y 3+ . 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 Yb 3+ is in good agreement with crystallographic ones: R =3.856 Å, R cryst =3.849 Å.