Irreversible Thermodynamic Description of Domain Occurrences in Ferroics

摘要

Based on the irreversible thermodynamics, a irreversible thermodynamic description of domain occurrences in ferroics such as ferroelectrics, ferromagnetics and ferroelastics was given. The ferroic domain structures occur at the ferroic phase transitions from the prototype phases to the ferroic phases. The processes of transition are stationary state processes so that the principle of minimum entropy production is satisfied. The domain occurrences are a consequence of this principle. The time-spatial symmetry related to the domains and their occurrences was also expounded. People have been familiar with the domain structures in ferroics for a long time. In history, people expounded and proved the rationalization of the existence of them [1-3], worked out the specific configurations of them basing on the principle of minimum free energy and the Curie principle in various cases [1-5], and investigated the dynamics of the movements of domains and domain walls (especially the domain switch) [6-9]. After all, the influence of domain structures on the properties of materials has been also intensively studied [10,11]. However, it has to be pointed out that the above involved thermodynamics is confined into the equilibrium range, which is the equilibrium thermodynamics (also called "thermostatics"). It concerns states rather than processes.