Relaxation of the 4S3/2 Level of Er3+ in Cs2NaErCl6
G. Dominiak-Dzik, S. Gołąb and W. Ryba-Romanowski
W. Trzebiatowski Institute for Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 937, 50-950 Wrocław, Poland
Full Text PDF
Octahedral (Oh) symmetry of the RE3+ sites in the Cs2NaRECl6 crystals removes all of the electric dipole intensity from the 4f-4f transitions. Thus the decay of luminescence originating in the excited states of RE ions is governed by phonon assisted (vibronic) transitions, multiphonon relaxation and phonon assisted energy transfer (cross relaxation and energy migration to impurities). Contribution of these processes to the decay of the 4S3/2 state of erbium in Cs2NaErCl6 has been studied in the 4.2-300 K temperature region. It has been concluded that at low temperatures the 4S3/2 state decays exclusively by vibronic transitions. At about 100 K the cross relaxation via the 4I9/2 state becomes operative. Efficiency of this process grows strongly with increasing temperature, reducing the 4S3/2 lifetime by almost three orders of magnitude. No evidence has been found that multiphonon relaxations contribute to the decay of the 4S3/2 state.
DOI: 10.12693/APhysPolA.84.941
PACS numbers: 78.55.Hx