New Oxide Materials for Advanced Electrooptical Applications: Defect structure as Related to Performance

Subproject LiNbO3       (G.Malovichko, V.Grachev)

 High resolution electron microscopy (HREM) investigations for congruent undoped LiNbO3 show clustered defects with a size of one or more nm (see Figure below). Models of planar and spatial correlated defects were developed and used for the simulation of HREM images. Neither randomly distributed antisite defects, compensated by lithium or niobium vacancies, nor clustered lithium and oxygen vacancies can count for the contrast variations in the observed images. A new model of small Nb2O5 clusters is suggested.

hrem

HREM image of congruent lithium niobate

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After: Ch.Leroux, G.Malovichko, G.Nihoul, V.Grachev, C.Boulesteix. High resolution electron microscopy investigation of correlated defects in non-stoichiometric lithium niobate. - J. Phys. Chem. Solids, v. 59, No 3, pp. 311-319, (1998).