Domain Structure and Birefringence in Pyridinium Perchlorate and Pyridinium Fluoroborate Single Crystal
B. Kosturek and Z. Czapla
Institute of Experimental Physics, Wrocław University, pl. M. Borna 9, 50-204 Wrocław, Poland
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Received: 24 06 2004
Pyridinium perchlorate and pyridinium fluoroborate were grown and their successive phase transitions were studied by means of polarized microscopic observations and measurements of linear birefringence temperature changes. The microscopic observations revealed domain structure appearance at 245 K and 238.7 K for pyridinium perchlorate and pyridinium fluoroborate, respectively. This domain structure exists also in lower phases. Birefringence measurements confirmed two first-order phase transitions at 245.3 K and 231.5 K for pyridinium perchlorate and two continuous phase transitions at 238.7 K and 205.4 K for pyridinium fluoroborate.
DOI: 10.12693/APhysPolA.106.529
PACS numbers: 77.80.Bh