The infra-red absorption of OT-, OD- and OH- ions was used to monitor the behavior of the isotopes in monocrystalline samples. The T atoms were produced by transmutation of the 63Li nucleus via a (10n, 42He) reaction involving thermal neutrons. The OD- ions were added to the crystal by heat-treatment in D2O vapor. There were several configurations for each isotope, and each configuration was common to all 3 isotopes. The absorption data were used to deduce the diffusion coefficients at temperatures of between 900 and 975K (table 97). The activation energies for H and T out-diffusion were 1.9 and 1.8eV, respectively.
R.Gonzalez, C.Ballesteros, Y.Chen, M.M.Abraham: Physical Review B, 1989, 39[15], 11085-92
Table 97
Diffusion of Hydrogen Isotopes in LiNbO3
Temperature (K) | Isotope | Method | D (cm2/s) |
900 | H | out-diffusion | 8.0 x 10-8 |
930 | H | out-diffusion | 1.2 x 10-7 |
960 | H | out-diffusion | 2.9 x 10-7 |
975 | H | out-diffusion | 4.7 x 10-7 |
900 | T | out-diffusion | 1.2 x 10-7 |
930 | T | out-diffusion | 1.3 x 10-7 |
960 | T | out-diffusion | 2.4 x 10-7 |
975 | T | out-diffusion | 3.6 x 10-7 |
960 | D | out-diffusion | 3.7 x 10-7 |
975 | D | in-diffusion | 4.5 x 10-7 |