The Incommensurate Phase of Betaine Calciumchloride-Dihydrate

Betaine Calciumchloride-Dihydrate (BCCD), (CH 3 ) 3 NCH 2 COO·CaCl 2 ·H 2 O, is the first member of the (TGS, TSCC)-family which shows incommensurate behaviour. The phase transitions were investigated by conventional X-rays Double axis diffractometer “AMADEUS”, Saarbrücken) and by synchrotron radiat...

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Bibliographic Details
Published in:Japanese Journal of Applied Physics 1985-01, Vol.24 (S2), p.826
Main Authors: Brill, W., K. H.Ehses, K. H.Ehses
Format: Article
Language:English
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Summary:Betaine Calciumchloride-Dihydrate (BCCD), (CH 3 ) 3 NCH 2 COO·CaCl 2 ·H 2 O, is the first member of the (TGS, TSCC)-family which shows incommensurate behaviour. The phase transitions were investigated by conventional X-rays Double axis diffractometer “AMADEUS”, Saarbrücken) and by synchrotron radiation (two-axis-diffractometer Hasylab/DESY, Hamburg). Above 164 K there is a high temperature phase and below 43 K a ferroelectric phase In between, the incommensurate phase can be described as an “incomplete devil's staircase”. The temperature dependence of the satellite intensity can be fitted by a critical exponent 2β=0.85. The half width of the satellite reflections exhibits anomalous behaviour at the transition temperatures. The modulation vector is influenced in a very special manner by an external electric field.
ISSN:0021-4922
1347-4065
DOI:10.7567/JJAPS.24S2.826