Effect of Point Defects Induced by <TEX>${gamma}$</TEX>-Irradiation on the Phase Transition in TGSe Crystal

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J. Korean Ceram. Soc. > Volume 36(8); 1999 > Article

Journal of the Korean Ceramic Society 1999;36(8): 859.

${gamma}$선 조사에 의한 점결함이 Triglycine Selenate(TGSe) 결정의 상변화에 끼치는 영향

송용원

고려대학교 재료공학과

Effect of Point Defects Induced by ${gamma}$-Irradiation on the Phase Transition in TGSe Crystal

ABSTRACT

The influence of radiation induced defects on the thermodynamic properties in triglycine selenate(TGSe) crystal was studied by calorimetric experiments. The Landau phenomenological theory of ferroelectric phase transition was used to explain the thermodynamic properties and all free energy expansion coefficients were determined. The successive shift of the phase transition to the lower temperature occurred with ${gamma}$-irradiation dose. In this case the concentration of defects(dose of ${gamma}$-irradiation) can be considered as an independent thermodynamic parameter like hydrostatic pressure or deuterium contents which were used to study properties of this crystal. The phase transition shift for TGSe was -0.94 K/MR

Key words: ${\gamma}$-irradiation, Phase transition, Ferroelectrics, Landau free energy, Heat capacity