11 research outputs found

    Statistical theory of thermodynamic and dynamic properties of the RbHSO4_{4} ferroelectrics

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    Within the modified four-sublattice model of RbHSO4_{4} with taking into account the piezoelectric coupling to the strains εi\varepsilon_i, ε4\varepsilon_4, ε5\varepsilon_5, and ε6\varepsilon_6, the polarization components, static and dynamic dielectric permittivity of clamped and free crystal are calculated in the mean field approximation. At the proper choice of the values of the theory parameters, a satisfactory quantitative description of the available experimental data is obtained.Comment: 16 pages, 15 figure

    Thermodynamic and dynamic dielectric properties of one-dimensional hydrogen bonded ferroelectric of PbHPO4_4-type

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    Within the modified model of proton ordering of one-dimensional ferroelectric having hydrogen bonds of PbHPO4_4-type, their thermodynamic and dynamic characteristics are studied and calculated taking into account the linear (by crystal deformations εi\varepsilon_i (i=1,3i=1,3) and ε4\varepsilon_4) contributions into the energy of a proton system but without taking into account the tunneling in the two-particle cluster approximation. There has been obtained a good quantitative description of the temperature dependence of polarization, static dielectric permittivity, heat capacity and frequency dependence of dynamic dielectric permittivity at different temperatures for PbHPO4_4 and PbHDO4_4 crystals.Comment: 12 pages, 7 figure

    Dynamic properties of NH3_3CH2_2COOH\cdotH2_2PO3_3 ferroelectric

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    Using a modified pseudospin model of NH3_3CH2_2COOH\cdotH2_2PO3_3 ferroelectric taking into account the piezoelectric coupling with strains εi\varepsilon_i, ε4\varepsilon_4, ε5\varepsilon_5 and ε6\varepsilon_6 within Glauber method in two-particle claster approximation, we have calculated components of dynamic dielectric permittivity tensor and relaxation times of the model. At the proper set of theory parameters, frequency and temperature dependences of the components of permittivity and temperature dependences of the relaxation times are studied. A satisfactory agreement of the theoretical results with experimental data for longitudinal permittivity is obtained.Comment: 13 pages, 11 figure

    Influence of the uniaxial stress p2p_2 and transverse fields E1E_1 and E3E_3 on the phase transitions and thermodynamic characteristics of GPI ferroelectric materials

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    A modified GPI model that accounts for the piezoelectric coupling between the ordered structural elements and the strains εj\varepsilon_j has been used for studing of effects arising in GPI ferroelectrics under the action of the uniaxial stress p2p_{2} and electric fields E1E_1 and E3E_3. The polarization vectors and components of static dielectric permittivity are calcucated in the two-particle cluster approximation for mechanically clamped crystal, and piezoelectric and thermal parameters are also determined. The influence of the simultaneous action of the stress p2p_{2} and fields E1E_1 and E3E_3 on the phase transition and physical characteristics of GPI crystal has been studied.</jats:p
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