FERROELECTRICITY AND CONDUCTION IN FERROELECTRIC CRYSTALS.
Technical rept. 1 Mar 67-29 Feb 69,
PENNSYLVANIA STATE UNIV UNIVERSITY PARK MATERIALS RESEARCH LAB
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Work on this contract has contributed to advances in the understanding of ferroelectricity in crystals. In gadolinium molybdate it was shown that the ferroelectric phase below 159 degrees C arises due to an elastic instability in the piezoelectric prototype structure forcing a switchable polar state. A new general formulation of the possible orientation of permissible domain walls in reversible ferroelectric crystals was completed. Work on this contract has contributed to the understanding of ferroelectricity in bismuth titanate Bi4Ti3O12, and in other bismuth oxide type layer structures. In ferroelectric studies at low temperature, it has been shown that in lithium thallium tartrate monohydrate, which has a Curie temperature at 12 degrees K, the true weak field permittivity does not show a Barrett-type anomaly. New measurements have been made of the dielectric polarization and magneto-dielectric effects in the ferrimagnetic-ferroelectric nickel iodine boracite.
- Electricity and Magnetism
- Solid State Physics