Abstract
Measurements of the three components of the birefringence of betaine calciumchloride dihydrate (BCCD) in the range from 170 to 30K are reported. Clear anomalies are observed at the normal-incommensurate transition and at the transitions which connect low-order commensurate phases. The birefringence remains, however, unsensitive to high-order commensurate phases, among them, the phase with q=27, in the range 127–125K. The critical behaviour of the spontaneous birefringence at the normal- incommensurate transition at 164K has been studied. The resulting critical exponent is 2β∼0.76. The possibility that this phase transition takes place in two steps with a narrow intermediate phase, as suggested recently, has been carefully examined. The existence of two separate anomalies could not be confirmed. In general, the present results are compatible with the conventional model of a single order parameter for the whole transition sequence.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
