Dielectric Properties of Cholesteryl 2, 2, 3, 3-Tetrafluoropropionate under Hydrostatic Pressure
Year: 1984
Type: article
Abstract: The dielectric properties of cholesteryl 2, 2, 3, 3-tetrafluoropropionate were measured under hydrostatic pressures of up to 5 kbar. The reciprocal permittivity ε -1 was found to vary almost linearly with temperature T in the normal phase I under a pressure p, and the peak value of ε at the I-II (normal-incommensurate) phase transition temperature T I-II increased with increasing p in the low-pressure region below 3 kbar and tended to saturate in the high-pressure region above 3 kbar. The slope of T I-II against p was 6°C/kbar in the low-pressure region and decreased in the high-pressure region. The dielectric relaxation curves in phase II shifted towards higher temperatures with p, while the relaxation frequency decreased with p at constant temperature. The relaxation curves converged at the II-III (incommensurate-incommensurate) phase transition temperature T II-III with decreasing frequency under pressure. The pressure dependence of activation parameters such as the enthalpy, entropy and volume was also estimated. The slope of T II-III against p was 1.6°C/kbar in the low-pressure region and increased in the high-pressure region. The region of phase II was found to be extended in the low-pressure region and narrowed in the high-pressure region by the application of pressure.
DOI: 10.1143/jjap.23.556
Institution: Gifu University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2053318713