Ionic conductivity in lithium niobate

The diffuse X-ray scattering obtained from congruent melting lithium niobate crystals is interpreted on the basis of both static and dynamic models of crystal disorder. The static displacements of atoms within an expanded chain introduced for superionic conductors are discussed as one reason for ionic conductivity of lithium niobate. The dynamic disorder model introduced for some perovskites describing anharmonic oscillations of ions and thereby possible migration traces is the second ionic conductivity model discussed. The determined directions <22.1> of possible ionic conductivity are identical in both cases: with respect to, e.g. a lithium niobate rotated Y-cut wafer, one of these directions is perpendicular to the surface acoustic wave (SAW) propagation direction and parallel to the wafer surface