Comparison of and comments on two thermodynamic approaches (reversible and irreversible) to ferroelectric phase transitions

• Published in: Phase transitions Vol. 81; no. 5; pp. 479 - 490
• Main Authors: Ai, Shu-Tao, Xu, Chang-Tan, Wang, Yong-Long, Zhang, Shao-Yin, Ning, Xue-Feng, Noll, Eli
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 01.05.2008
• Subjects: ferroelectric phase transition; irreversible thermodynamics; Landau-Devonshire theory; non-equilibrium variational principles
• ISSN: 0141-1594; 1029-0338
• DOI: 10.1080/01411590701877913

In this article, we compared and commented on two thermodynamic approaches, i.e. the reversible and irreversible ones to ferroelectric phase transitions especially in the case of first-order. The reversible approach, otherwise known as the Landau-Devonshire theory proved not to possess a firm physical basis according to the concepts and methods originating from the field theory and those originating from the analytical dynamics. The metastable states hypothesis underlying the Landau-Devonshire theory causes an unpleasant consequence and a logical conflict. As for the new-developed irreversible approach, we demonstrated that the fundamental hypothesis of stationary states underlying it, is reliable with the aid of non-equilibrium variational principles. The difficulties encountered within the Landau-Devonshire theory can be overcome while this approach is applied to the first-order ferroelectric phase transitions. There is some justification made to prove the proposition.