Author： Rubio-Peña L. Breczewski T. Bocanegra E. H.
Publisher： Taylor & Francis Ltd
ISSN： 0015-0193
Source： Ferroelectrics, Vol.269, Iss.1, 2002-01, pp. : 171-176
Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.
Abstract
Decreasing the temperature, the urea inclusion compounds with n-alkanes guest molecules exhibit the phase transitions. The symmetry superspace group of low temperature phase is not yet established. A difficulty arises due to the large number of domains generated at this phase transition. Therefore, the domain structure in the low temperature phase and the phase boundaries of the n-nonadecane/urea and n-heptadecane/urea crystals has been studied by direct observation under polarized light in the temperature range 293 K - 100 K. The phase transitions at 159 K in the urea/n-heptadecane crystals and at 158 K in urea/n-nonadecane has been observed. By applying an external, compressive and unidirectional mechanical stress, the ferroelastic character of the domains has been confirmed. The observed switching process among the different domains can be understood as a mechanism that minimizes the elastic energy.
Related content
Access to resources
Recommend
