Spin-glass model with essential short-range competing interactions

Abstract

We consider a proton-glass model with an arbitrary range of competing interactions within two-particle cluster approximation for the free energy and within symmetric replica approach. We show that for the thermodynamic characteristics, the Gaussian approximation for distribution functions of cluster fields can be used. For a simpler proton-glass model with weak long-range interactions (linear approximation) we study the effect of the long-range interactions and random internal fields on the phase diagram and thermodynamics characteristics. It is shown that small fluctuations of internal fields can lead to essential smearing of proton-glass transition region. The adaptability of the theory for a description of proton-glasses of Rb_1-x(NH₄)_xH₂PO₄-type is discussed

Thermodynamics and complex dielectric permittivity of mixed crystals of the Rb_{1-x}(NH_{4})_{x}H_{2}PO_{4} type

“…In [40,41] a theory of static properties of model proton glasses with an arbitrary range of competing interactions was proposed. Thermodynamic properties of the model with essential short-range and weak long-range interactions were explored within the two-particle cluster approximation.…”

“…Thermodynamic properties of the model with essential short-range and weak long-range interactions were explored within the two-particle cluster approximation. In the present paper, the approaches developed in [39][40][41] are used to describe thermodynamic and dielectric properties of hydrogen bonded…”

Thermodynamics, dielectric permittivity and phase diagrams of the Rb_{1-x}(NH_{4})_{x}H_{2}PO_{4} type proton glasses

“…In [78][79][80][81] a theory of static characteristics of model proton glasses with an arbitrary range of competing interactions has been proposed. In [82,83] a similar approach has been used for the description of some thermodynamic characteristics and transverse dielectric permittivity of hydrogen bonded Rb 1−x (ND 4 ) x D 2 PO 4 and Rb 1−x (NH 4 ) x H 2 AsO 4 compounds, in which an essential role in the formation of energy levels is played by the proton short-range correlations.…”

Microscopic Theory of Rb1 - x(NH4)xH2PO4Type Compounds

“…Mixed deuteron ferroelectric-antiferroelectric systems of Rb 1−x (ND 4 ) x D 2 PO 4 type, in which a proton glass state is realized at low temperatures, have been intensively studied both experimentally [1][2][3][4][5] and theoretically [6][7][8][9][10].…”

“…In the present paper the cluster approach suggested in [10] for proton-glass models is elaborated for description of thermodynamic and dielectric properties of hydrogen bonded Rb 1−x (NH 4 ) x H 2 PO 4 type compounds. Details of the theory are given in [11].…”