Single crystals of Pb1-xBaxNb2O6, where (1 - x) ranged from 0.5 to 0.6, were grown by using the vertical Bridgman method. The OH- absorption spectra were measured by means of Fourier-transform infra-red spectrometry. The as-grown crystals exhibited a strong OH- absorption near to 3485/cm, thus revealing the existence of H+. The polarization dependence of the integrated OH- optical-absorption intensity showed that all of the O-H bonds were polarized either perpendicular or parallel to the c-axis; with a greater proportion being perpendicular. The proton concentration could be increased by heat treatment in a humid atmosphere, and was decreased by an ambient or O atmosphere. The diffusivity of protons perpendicular to the c-axis was measured in Pb0.5Ba0.5Nb2O6 by means of proton in-diffusion measurements. It was found that Do was equal to 2.19 x 10-7cm2/s at 750C. This was comparable to the proton diffusivities in TiO2 (1.90 x 10-6cm2/s) and LiNbO3 (1.93 x 10-7 to 2.51 x 10-6cm2/s) at the same temperature. The proton activation energy was 0.95eV.

M.Lee, R.S.Feigelson, A.Liu, L.Hesselink, R.K.Route: Physical Review B, 1997, 56[13], 7898-904