SKM 2023 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 13: Polar Oxide Crystals and Solid Solutions I
KFM 13.3: Vortrag
Donnerstag, 30. März 2023, 10:40–11:00, POT 106
Hydrogen Diffusion in LiNbO3 and LiTaO3 — •Kofahl Claudia1, Dörrer Lars1, Suhak Yuriy2, Yakhnevych Uliana2, Fritze Holger2, and Schmidt Harald1,3 — 1Institut für Metallurgie, AG Festkörperkinetik, TU Clausthal, Germany — 2Institut für Energieforschung und Physikalische Technologien, TU Clausthal, Germany — 3Clausthaler Zentrum für Materialtechnik, TU Clausthal, Germany
LiNbO3 and LiTaO3 crystals are technologically important polar metal oxides with exceptional combinations of ferroelectric, piezoelectric, acoustic, optical and ion conductivity properties. The presence and diffusion of H in these materials has an important influence on the materials properties, reducing optical damage, increasing optical birefringence and changing ionic conductivity. The diffusion mechanism is unclear up to now. Therefore, it is of particular interest to study the diffusion of hydrogen. For this purpose, we use two different analytical methods, SIMS (Secondary Ion Mass Spectroscopy) and IRS (Infrared Spectroscopy). For the SIMS measurements, the crystals are loaded with high amounts of H by means of proton-exchange and the redistribution of H is monitored after post-annealing. In contrast, for the IRS experiments, only hydrogen of about 300 ppm, which is introduced by crystal growth in air, is replaced by deuterium during exchange anneals in D2O. The measured diffusion coefficients of the two methods differ from each other, but are higher than Li diffusivities as given in literature. The activation energies are similar. Possible reasons for the differences are discussed.