Scanning for Ferroelectricity in Polycrystalline Materials.
CASE WESTERN RESERVE UNIV CLEVELAND OHIO DEPT OF MACROMOLECULAR SCIENCE
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A method has been developed which can scan rapidly for ferroelectricity in polycrystalline compounds. This consists of measuring the dielectric constant of a polycrystalline pellet as a function of temperature. If any dielectric anomalies are found where the dielectric and loss tangent peaks are independent of frequency, a solidsolid first order transition has been found. If the sample is held under a voltage gradient while the temperature is dropped through the transition temperature, charge storage shows poling of the sample and therefore ferroelectric behavior. The procedure was demonstrated on thiourea, a known ferroelectric. 2-Ethyl benzimidazole showed the same phenomena at a transition temperature of -90C and is probably a new ferroelectric material.
- Physical Chemistry
- Solid State Physics