Structural and morphological characterization of flux grown YTa7O19, Nd:YTa7O19, Nd:LaTa7O19 and NdTa7O19 crystals

YTa7O19 (YHT), Nd:YTa7O19 (Nd:YHT), Nd:LaTa7O19 (Nd:LHT) and NdTa7O19 (NHT) single crystals have been grown by spontaneous nucleation from high-temperature solutions using K2Mo3O10–B2O3 as a flux and structurally characterized by X-ray diffraction techniques. The effect of the flux composition on the crystal morphology is discussed. The distribution of the Nd3+ ions in doped crystals has been investigated by electron microprobe analysis, evidencing non-uniform segregation coefficients. The Raman spectra of the investigated compounds are presented, and a reinterpretation of the fine structure present in the optical spectra is proposed in the light of the crystallographic information.