Ferroelectricity and Conduction in Ferroelectric Crystals.
Technical rept. (Final) 1 Mar 69-1 Mar 72,
PENNSYLVANIA STATE UNIV UNIVERSITY PARK MATERIALS RESEARCH LAB
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Work on this contract has provided a basis for the phenomenological correlation of the dielectric, elastic, and electro-optic properties of bismuth titanate Bi4Ti3O12. Detailed x-ray and neutron diffraction studies of Bi4Ti3O12 have given the symmetry and atomic coordinates in the ferroelectric phase, and taken with structural studies on other bismuth titanate family compounds, provided the basis for an atomistic description of ferroelectricity in this family. For the ferroelastic-ferroelectric lithium thallium tartrate monohydrate, the phase change at 12K is shown to arise through unusually strong piezoelectric coupling. Initial studies of lead germanate Pb5Ge3O11 suggest that the optical rotation domains in this crystal may offer new possibilities in electro-optic domain state devices. The basic arrangement in the crystal structure has been elucidated and a range of crystal chemical substitutions demonstrated, which preserve the ferroelectric properties. Author
- Solid State Physics