Single crystal structure determination and infrared fluorescence of the system (K_3Sr_(1-x)Nd_x) (Nd_(1-x)Sr_(1+x)) Nb_(10)O_(30)

摘要

The μ-pulling down technique has permitted to grow single crystal fibers, of the gross chemical formula K_3Sr_2NdNb_(10)O_(30), having a sufficient optical quality to carry out spectroscopic studies. The crystal structure has been determined and refined to reliability factors: (i) R_1 = 0.0384 (wR_2 = 0.0665) at room temperature; (ii) R_1 = 0.0334 (wR_2 = 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 Nd~(3+) ions located in both Sr~(2+) and K~+ sites with 15- and 12-fold coordination, respectively.