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Comparison of critical fluctuations in Sn2P2S6 and Sn2P2(Se0.28S0.72)6 crystals
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Dzyubanski V., Shopa R., Kushnir O. and Vlokh R.

We report on the quantitative parameters of fluctuation effects observed in the birefringence and linear thermal expansion of Sn2P2(SexS1-x)6 crystals with x = 0 and 0.28. These parameters, including the Ginzburg number that governs the temperature width of the scaling region, are found to be of the same order of magnitude. The relevant implications concerned with the influence of structural defects and multicritical points on the phase diagram are discussed.

Keywords: Sn2P2(SexS1-x)6 crystals, phase transitions, critical fluctuations, multicritical points

PACS: 77.80.Bh, 77.84.Bw, 64.60.Kw, 61.72.Hh, 78.20.Fm, 65.70.+y
UDC: 535.5, 548.0
Ukr. J. Phys. Opt. 12 19-27 
doi: 10.3116/16091833/12/1/19/2011
Received: 30.12.2010

Анотація. У роботі наведено кількісні параметри флуктуаційних ефектів, які спостерігаються в двозаломленні та лінійному термічному розширенні кристалів Sn2P2(SexS1-x)6 із x = 0 and 0.28. Виявлено, що ці параметри, включно з числом Гінзбурга, яке  обумовлює температурну ширину діапазону скейлінгу, за порядком величини однакові. Обговорено відповідні наслідки, пов’язані із впливом структурних дефектів та існуванням полікритичних точок на фазовій діаграмі.
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