Phase diagram and static dielectric susceptibility of hydrogen bonded ferro–antiferroelectric mixed compounds

Dipole glass parameter behaviour for ferro-antiferroelectric solid mixtures

“…The difference between RADA phase diagram in [28] and the one presented here is the line dividing the paraelectric phase and the antiferroelectric phase (P-AF). In figure 1 the upper line represents the points of stable non-zero root arising for antiferroelectric order parameter q while in [28] the corresponding line indicates the points of its bifurcation (lower line in figure 1). It should be noted that the…”

“…We will regard a regular KDP-type crystalline lattice, each site of which is randomly occupied by rubidium atoms or ammonium groups, that is by Rb or NH 4 . The effective Hamiltonian of this mixed system is taken in the form [28,30]:…”

“…Computing the equations (2.8) one can find the dependencies of P , q, g z , g x parameters on temperature T and concentration n. Those dependencies form a phase diagram of the investigated ferroantiferroelectric mixed system in the plane n − T . The principal outline of a phase diagram for RADA system was obtained in the paper [28], but due to its considerable role in the analysis of the mixed system behaviour, we reproduced it here ( figure 1).…”

“…In our previous papers [26][27][28], a new approach to the study of hydrogen bonded ferro-antiferroelectric solid mixtures of Rb n (NH 4 ) 1−n H 2 AsO 4 (RADA) type was suggested. It is based on the concept of a decisive role of microscopic structure of a system (single and pair correlation functions) in the formation of a dipole glass phase.…”