Spectroscopy ofEu3+ions in congruent strontium barium niobate crystals

Abstract

The optical properties of single crystals of strontium barium niobate, grown from the congruently melting composition and doped with different amounts of europium, are investigated. Absorption and emission spectra are measured in the visible and infrared spectral regions at different temperatures. From the spectra, conclusions on the structural sites can be drawn, revealing the major occupations of the B1 and B2 sites, and a minor one of the A2 site. The data are used to calculate crystal-field parameters for the mainly occupied site. A Judd-Ofelt analysis shows that the radiative quantum efficiency is approximately 70%. Furthermore, the influence of europium doping on the phase-transition temperature is determined.

Site location and crystal field ofNd3+ions in congruent strontium barium niobate

“…In fact, the above mentioned cationic disorder, together with a certain disorder on the anionic ͑oxygen͒ sublattice of SBN ͑Ref. 22͒ produce optical bands with a strong inhomogeneous broadening for the rare earth ions, 13,14,19,[23][24][25] as commented above for the 4 I 9/2 → 2 P 1/2 transition of Nd 3+ ions ͑see inset in Fig. 2͒.…”

“…19,20 The lattice location of Eu 3+ ions has been also investigated in congruent SBN crystals grown by different methods. 13,21 It seems that the growth method affects the site location of these ions: while in SBN crystals slowly grown at high temperatures by using the Czochralski technique the B octahedral sites seems to be favored, 13 crystals grown at lower temperatures by spontaneous nucleation in a flux the Eu 3+ ions seem to occupy mainly the A1 site.…”

“…In addition, the phase transition temperature depends on both host stoichiometry ͑i.e., on x, 0.25Յ x Յ 0.75͒ 1,10 and on the doping ions and their concentration. [11][12][13] It has been recently shown that the luminescence of Nd 3+ ions in congruent ͑x = 0.6͒ SBN crystal is almost insensitive to phase transition, while that of Tm 3+ and Yb 3+ ions is highly sensitive to temperature changes around the Curie temperature. 14 This different spectral sensitivity of the rareearth ions to the phase transition was proposed to be related to the different distribution of the rare earth ions among the available cationic sites in the ferroelectric SBN crystal host.…”

Absorption spectroscopy and energy levels of rare earth impurity centres in Srx Ba1–xNb2O6 crystals

“…The infrared spectrum of Yb 3+ absorption consists of large number of spectral lines due to possible occupation of the lattice sites of different origin by Yb 3+ as discussed in [10]. Since Yb 3+ demonstrate very strong electronphonon coupling effect in different host lattices and lattice disorder, the observed absorptions lines of Yb 3+ are broader than for the other RE ions.…”

Luminescence properties of Ba2NaNb5O15 crystals activated with Sm3+, Eu3+, Tb3+ or Dy3+ ions

“…We can then reliably suppose that the active ions have the same local structure in BNN and SBN. In this connection however, a recent paper has evidenced that the site occupancy of Eu 3 + in SBN depends on the growth conditions [17]. It is then worth to point out that the mentioned similarity concerns Eu:SBN grown by spontaneous nucleation in a strontium barium tetraborate flux by Bettinelli et al [16] who, on the basis of EXAFS measurements, located the Eu 3 + ions in the 12-fold A 2 sites of the SBN lattice.…”