Depth profiles of the proton concentration in proton-exchanged samples were measured by means of secondary ion mass spectrometry. The concentration-dependent diffusion coefficient for proton-Li counter-diffusion was then determined by using the Boltzmann-Matano method. The results (figure 27) obeyed Arrhenius relationships, and their analysis yielded activation energies of 78.6, 66.5 and 82.4kJ/mol for X-cut, Y-cut and Z-cut specimens, respectively. The results also depended upon the Li content of the proton exchange source (which was present as the benzoate).

The Dependence of the Diffusion Coefficient on the Proton Concentration in the Proton Exchange of LiNbO3. K.Ito, K.Kawamoto: Japanese Journal of Applied Physics - 1, 1997, 36[11], 6775-80