OH- OD- STRETCHING VIBRATION MODE OF FERROELECTRIC LI-1-XKXNBO3 (X=0.05-SIMILAR-TO-0.6)/

UV-Vis and IR spectroscopic investigation was carried out at room temp erature for Li1-xKxNbO3(x=0.05 similar to 0.6) mixed crystals with OH- /OD- in-diffusion, vapor transport equilibration (VTE) and polarizatio n experiment. We found that Li1-xKxNbO3(x=0.05 similar to 0.6) mixed c rystals can be divided into two different groups by the melt compositi on. The composition of x=0.05 similar to 0.3 crystals are K-doped LiNb O3 (LN) crystals. On the other hand, the composition of x=0.4 similar to 0.6 crystals correspond to Li0.4K0.6NbO3 (KLN) crystals. The OH- st retching vibration mode at 3524 and 3502 cm(-1) in KLN (x=0.6) crystal s was first time reported here. The OH-/OD- absorption peak was only e nhanced by OH-/OD- in-diffusion treatment at about 430 degrees C in th is experiment. The OH- absorption peak in a-c plane depends on the bea m polarization, However, the OH- absorption peak in a-b plane does not show polarization dependence. But the OH- absorption peak was shifted to 3506 cm(-1) after VTE treatment in a-c plane.