Growth and 10 K spectroscopy of Nd3+ in NaBi(WO4)2 single crystal

The experimental procedures to grow Nd doped NaBi(WO4)(2) single crystals by the Czochralski method and the difficulties or limitations encountered for doping are described. Nd concentrations in the crystal up to 0.3X10(20) cm(-3) have been produced with optical quality. Polarised optical absorption and photoluminescence of Nd3+ ion in this host have been studied at 10 K and the relative energies of 90 levels have been determined. An attempt to explain the large observed spectroscopic line-widths has been conducted through crystal field calculations of these levels supposing either a single Nd position with C-2 symmetry or two centres both with S-4 point symmetry. The latter assumption produces energy differences between both optical centres that can justify the enlargement of lines, but it is not consistent with the OA intensity changes observed in polarised spectra. The coexistence of several sites with statistically modified ordering of the short range Na and Bi cation distribution is suggested to account for this disagreement. (C) 2001 Elsevier Science B.V. AU rights reserved.