ANISOTROPIC GLASSLIKE CHARACTERISTICS OF STRONTIUM BARIUM NIOBATE RELAXORS

The complex dielectric response of strontium barium niobate relaxor fe rroelectrics has been studied as a function of orientation and composi tion. The dielectric response was found to be strongly dependent on or ientation, in distinct comparison to the nearly orientation-independen t response found for Pb-based perovskite relaxors. Investigations of t he temperature dependence of the high-field polarization behavior foun d that the square-to-slim loop hysteresis transition occurred rapidly with increasing temperature. In addition, no deviations from Curie-Wei ss behavior were found, however two distinct linear regions were obser ved. An anisotropic dielectric glasslike model involving the freezing of heterophase fluctuations is then discussed in reference to the data .