Multifrequency spectroscopy of defects in complex oxides

Abstract The typical output of the one‐frequency methods is an image with a space resolution of the order of the used wavelength. Such images contain direct evidence about the space structure of a lattice or macroscopic defects; however, they are not very helpful for the study of the internal structure of the atomic‐size defects. Measurements which use sweeping of electromagnetic wave frequency or sweeping of an external parameter furnish spectra or dependencies of measured characteristics on the swept quantity. The spectra contain indispensable information about energetic characteristics of interactions of intrinsic and extrinsic defects with the lattice ions. Different frequencies in very wide region have to be used for the study of these interactions (multifrequency spectroscopy). An application of this new approach to defects in lithium niobate allowed to determine characteristics of various interactions with magnitudes from 10⁴ to 10¹⁶ Hz, and to correlate them with definite models of the defects. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)