Research on the Crystal Growth and Dielectric Properties of High Permittivity Ferroelectric Materials.
Annual rept. 1 Mar 83-29 Feb 84,
ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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Millimeter wave measurements on two tungsten bronze SBN and BSKNN have shown a strong temperature dependence for the permittivity and dielectric losses, with both decreasing at low temperatures down to 77K for the electric field parallel to the polar axis. The observed changes in epsilon and epsilon perpendicular to the polar axis are much less, being only 30-40. A temperature sensitive peak in the polar epsilon has been observed for some samples. SBN crystals doped with Ce and Fe and have been successfully grown under DARPA contract, and work is continuing on improvements in the overall crystal quality of this bronze. Work is also continuing on the growth of ceramic and single crystal BSKNN, and ceramic KLN for evaluation of the millimeter wave properties of large unit cell stuffed bronzes. Grain oriented, hot-pressed PBN is also being developed in order to examine the properties of morphotropic phase boundary bronze compositions.
- Physical Chemistry