Growth of Na modified potassium lithium niobate crystal by the Czochralski method

Transparent Na modified potassium lithium niobate (Na0.23K2.60Li1.82Nb5.35O15.70; NKLN) crystal was successively grown by the Czochralski method using RF induction heating from melt composition Na2O:K2O : Li2O:Nb2O5=2:30:25:43mol%. NKLN crystal showed a tetragonal tungsten bronze structure with lattice constants a=12.5446±0.0010Å and c=4.0129±0.0005Å at room temperature. The dielectric constant along the c-axis ε33 showed a sharp maximum around 480°C. Optical transmission edge was 370nm and optical transmission spectra showed no absorption at wavelengths ranging from 380 to 800nm. The structural and optical properties of NKLN were similar to those of the near stoichiometric KLN crystals. We believe that the growth of NKLN by the Czochralski method has an advantage for a large size and high-quality crystal.