Growth and characterization of Nd-doped Ca0.28Ba0.72Nb2O6 crystal
ABSTRACT We report the growth of a Nd-doped calcium barium niobate (Nd:CBN-28) single crystal using the Czochralski method. The point group and space group of Nd:CBN-28 are determined to be tetragonal 4mm and P4bm , respectively, and the effective segregation coefficients of Nd, Ca, Ba, and Nb are 0.988, 1.029, 0.992, and 0.985, respectively. The density of the material is 5.321 g cm -3 at 19.6 ° C , in good agreement with the theoretical value. Thermal expansion measurements reveal that during the heating cycle, the c -axis of Nd:CBN-28 undergoes both thermal contraction and thermal expansion, while at the same time there is only expansion along the a -axis. Specific heat measurements reveal that an anomaly appears at about 220 ° C due to a phase transition. The thermal diffusivity increases slowly with increasing temperature. The thermal conductivity of the crystal has been calculated from these results, and the phonon mean free paths l a and l c along the a - and c -axes of Nd:CBN-28 crystal are estimated. The transmission spectrum of Nd:CBN-28 crystal along the  direction has been measured.