ANISOTROPIC GLASSLIKE CHARACTERISTICS OF STRONTIUM BARIUM NIOBATE RELAXORS

The complex dielectric response of strontium barium niobate relaxor ferroelectrics has been studied as a function of orientation and composition. The dielectric response was found to be strongly dependent on orientation, in distinct comparison to the nearly orientation-independent response found for Pb-based perovskite relaxors. Investigations of the temperature dependence of the high-field polarization behavior found that the square-to-slim loop hysteresis transition occurred rapidly with increasing temperature. In addition, no deviations from Curie-Weiss behavior were found, however two distinct linear regions were observed. An anisotropic dielectric glasslike model involving the freezing of heterophase fluctuations is then discussed in reference to the data.