Lithium diffusion in congruent LiNbO3 single crystals at low temperatures probed by neutron reflectometry

作者：Hueger E; Rahn J; Stahn J; Geue T; Heitjans P; Schmidt H^*

来源：Physical Chemistry Chemical Physics, 2014, 16(8): 3670-3674.

DOI：10.1039/c3cp54939a

The self-diffusion of lithium in congruent LiNbO3 single crystals was investigated at low temperatures between 379 and 523 K by neutron reflectometry. From measurements on (LiNbO3)-Li-6 (amorphous film)/(LiNbO3)-Li-nat (single crystal) samples, Li self-diffusivities were determined in single crystals down to extremely low values of 1 x 10(-25) m(2) s(-1) on small length scales of 1-10 nm. The measured diffusivities are in excellent agreement with (extrapolated) literature data obtained by experiments based on Secondary Ion Mass Spectrometry and Impedance Spectroscopy. The tracer diffusivities can be described by a single Arrhenius line over ten orders of magnitude with an activation enthalpy of 1.33 eV, which corresponds to the migration energy of a single Li vacancy. A deviation from the Arrhenius behaviour at low temperatures, e.g., due to defect cluster formation is not observed.

• 出版日期2014