Publication
Title
Electron paramagnetic resonance study of rare-earth related centres in $K_{2}YF_{5}:Tb^{3+}$ thermoluminescence phosphors
Author
Abstract
 Rare-earth related centres have been investigated in K2YF5:Tb3+ crystals, exhibiting thermoluminescence (TL) below and above room temperature (RT), using electron paramagnetic resonance (EPR) spectroscopy at Q (34 GHz) and W-band (94 GHz). The spectra have been studied prior to irradiation, after exposure in the kGy range to X-rays at 77 K and subsequent pulse annealing up to 570 K. In addition to Gd3+, previously studied in detail, we identified Er3+ and Yb3+ centres as accidental impurities in as-grown crystals and determined their effective g tensors. The EPR spectra of irradiated and annealed crystals provide evidence for the production of at least three distinct Tb-related trapped hole centres, two of which could definitely be identified as Tb4+. Hence, we prove that the Tb3+ activator ions also act as hole traps in K2YF5. Pulse annealing experiments indicate that the TL above RT results from thermal release of electrons, recombining at these Tb4+ ions.
Language
English
Source (journal)
Optical materials. - Amsterdam
Optical materials. - Amsterdam
Publication
Amsterdam : 2011
ISSN
0925-3467
Volume/pages
33 :6 (2011) , p. 865-871
ISI
000289390000023
Full text (Publisher's DOI)
UAntwerpen
 Faculty/Department Research group Publication type Subject Affiliation Publications with a UAntwerp address