Thermodynamic Features of the System of Packed Antiferroelectric Chains

Abstract

The system is considered of Ising-like chains suffering the antiferroelectric instability. The interaction between the chains is taken into account within the framework of the molecular field approximation. Then summing over states of a single chain is carried out by the method making immediately use of the fact, that the unit cell can consist of several atoms. Such an approach may sometimes be more convenient than the transfer-matrix method. An appropriate phase diagram in an uniform external field is investigated. As a result, the electrical effects essentially must be small so that the corresponding measurements will be difficult in such systems. As an example the TIHF? structure is discussed.

Melting of inclusions with variable vacancy contents

“…The general picture of melting can also be more complicated owing to the possibility of the existence of some premelting states of inclusions [2]. As a result.…”

“…According to [ 2 , 31, the process of melting is associated with the transition of an inclusion to a state of high mobility, which is characterized by some atomic configuration with alarger number of unoccupied effective atomicpositions. For example.suchastate canbeachieved bythe transitionofoneatombelongingtoagiveninclusiontothecentral position in the corresponding cavity [2,3]. Then the other atoms fill the volume of the spherical layer between the central atom and the boundary of the cavity, provided that there is an appropriate decrease in the atomic sizes.…”