Abstract
The heat capacity of dimethyl ammonium-aluminum sulfate crystals (DMAAS), both nonirradiated and γ-irradiated to fluences of 107, 5×107, and 108 R, has been measured by the adiabatic method near the ferroelectric phase transition (PT) within the 80–300 K temperature range. The C p =f(T) curve exhibits a λ-shaped anomaly near the phase-transition point T C =152 K. The PT temperature and the magnitude of the anomaly are shown to decrease with increasing γ-irradiation fluence. It has been established that the ferroelectric PT at T C =152 K, which lies close to the tricritical point, shifts progressively more under γ irradiation toward the second-order PT, and that the behavior of the anomalous part of the heat capacity in the ferroelectric phase is described by the thermodynamic theory of Landau. The experimental heat-capacity data have been used to calculate the variation of the thermodynamic functions of the DMAAS crystal.
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Translated from Fizika Tverdogo Tela, Vol. 42, No. 5, 2000, pp. 922–924.
Original Russian Text Copyright © 2000 by Sheleg, Dekola, Tekhanovich.
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Sheleg, A.U., Dekola, T.I. & Tekhanovich, N.P. Effect of γ irradiation on the heat capacity of (CH3)2NH2Al(SO4)2 · 6H2O crystals near the ferroelectric phase transition. Phys. Solid State 42, 950–953 (2000). https://doi.org/10.1134/1.1131317
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DOI: https://doi.org/10.1134/1.1131317