Single crystal structure determination and infrared fluorescence of the system (K3Sr1−xNdx) (Nd1−xSr1+x) Nb10O30

The μ-pulling down technique has permitted to grow single crystal fibers, of the gross chemical formula K3Sr2NdNb10O30, having a sufficient optical quality to carry out spectroscopic studies. The crystal structure has been determined and refined to reliability factors: (i) R1 = 0.0384 (wR2 = 0.0665) at room temperature; (ii) R1 = 0.0334 (wR2 = 0.0638) at 120 K. Difference in the cationic distribution over the 15- and 12-fold sites was noticed. IR fluorescence spectra investigated under different laser excitation wavelength at 300 K and 77 K show strong emissions at 0.9 and 1.06 μm. Low temperature fluorescence behavior is compatible with Nd3+ ions located in both Sr2+ and K+ sites with 15- and 12-fold coordination, respectively.

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► Single crystals of TTB-K3Sr2NdNb10O30 have been grown by two different methods.
► The structures were refined using occupation ratio of Nd3+ in pentagonal sites.
► The crystal chemical formulas depend on the route of crystal preparation.
► Luminescence results corroborate the distribution of Nd3+ ions over two sites.