Accession Number : AD0286036

Title :   A STUDY OF FERROELECTRIC MATERIALS

Corporate Author : CAMBRIDGE UNIV (ENGLAND) CAVENDISH LAB

Personal Author(s) : TAYLOR,W.H.

Report Date : 25 SEP 1962

Pagination or Media Count : 1

Abstract : The high-temperature structures of NaNbO3, radiation effects in ferroelectric materials, and neutron scattering with certain hydrogenous materials and materials showing dielectric anomalies are studied. For the study of the structure at high temperatures methods were developed for obtaining X-ray single-crystal photographs up to 900 C. At 540 C a tetragonal perovskite-type structure was confirmed. The super lattice reflexions associated with 2- and 4- sub cell repeats were found at lower temperatures. A ferroelectric material, on irradiation by neutrons, gamma rays or X-rays, acts as a source of electrical energy. Two types of this radiation-sensitivity were observed: one variable and of short time-constant, seen for periods of seconds or minutes after the start of irradiation; the other of long time-constant and stable for months after irradiation. Attempts to correlate radiation-sensitivity and thickness of sample were unsuccessful. The neutron spectra of ferroelectric and paraelectric BaTiO3, and of a number of hydrogen-bonded structures, were studied and partially interpreted. Evidence was obtained for the existence of a dielectric anomaly at about 20 K. in TlCl and 50 K. in TlBr. (Author)

Descriptors :   *FERROELECTRIC MATERIALS, *NIOBATES, *SODIUM COMPOUNDS, BARIUM COMPOUNDS, BROMIDES, CHEMICAL BONDS, CHLORIDES, DIELECTRIC PROPERTIES, HIGH TEMPERATURE, LOW TEMPERATURE RESEARCH, MOLECULAR STRUCTURE, NEUTRON SCATTERING, RADIATION EFFECTS, REFLECTION, SINGLE CRYSTALS, THALLIUM COMPOUNDS, TITANATES, X RAY PHOTOGRAPHY

Distribution Statement : APPROVED FOR PUBLIC RELEASE