Dynamics of ferroactive crystals of orthophosphate type

Levitsky, R. R.; Korynevsky, N. A.; Stasjuk, I. V.

doi:10.1080/00150197808237303

Cited by 8 publications

(10 citation statements)

References 1 publication

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“…The dynamics of the KDP family crystals was studied in [16] within the fourparticle cluster approximation within the framework of the approach developed in [17,18]. It has been shown for the first time that dynamic characteristics of these crystals are essentially affected by an effective tunnelling parameter, renormalized by short range interactions.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics and Dielectric Properties of the Nh_4h_2po_4 Type Antiferroelectrics

Levitskii¹,

Lisnii²,

Baran³

2002

Condens. Matter Phys.

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Within the framework of the proton model we study thermodynamic and static dielectric properties of the ADP type antiferroelectrics with taking into account the tunnelling effects of protons on hydrogen bonds. In the fourparticle cluster approximation for the short-range interactions and in the mean field approximation for the long-range interactions we calculate the free energy, entropy, and components of static dielectric susceptibility of the crystals. We also get the system of equations for the sublattice proton order parameter and an equation for the phase transition temperature. We find the values of the theory parameters for the NH 4 H 2 PO 4 and NH 4 H 2 AsO 4 crystals and get a good agreement between the theoretical results and the corresponding experimental data for the temperature dependences of the spontaneous sublattice polarization, proton specific heat, longitudinal and transverse static dielectric permittivities of the crystals.

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Section: Introductionmentioning

confidence: 99%

Thermodynamics and Dielectric Properties of the Nh_4h_2po_4 Type Antiferroelectrics

Levitskii¹,

Lisnii²,

Baran³

2002

Condens. Matter Phys.

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“…Before going into the discussion of the proposed in previous sections theory, let us note that, strictly speaking, this theory can be valid for a completely deuterated KD 2 PO 4 crystal only, whereas the vast majority of experimental data concerns the crystals, deuterated partially (see [11,12,13,14,15,16]). Nevertheless, as the relaxational character of dielectric dispersion in K(H 1−x D x ) 2 PO 4 crystals implies, tunneling effects in them are most likely suppressed by the short-range correlations between hydrogens [19,20,21]. So at least in the case of high deuteration, we are allowed to neglect tunneling and apply the theory to partially deuterated crystals as well.…”

Section: Discussionmentioning

confidence: 99%

INFLUENCE OF sigma_1-sigma_2 STRESS ON PHASE TRANSITION AND PHYSICAL PROPERTIES OF KD_2PO_4-TYPE FERROELECTRICS

Stasyuk¹,

Levitskii²,

Zachek³

et al. 2001

Condens. Matter Phys.

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Within the proposed earlier model we study effects of stress σ 1 − σ 2 on the KD 2 PO 4 type ferroelectrics. In the cluster approximation for the short-range correlations, we calculate dielectric, piezoelectric, and elastic characteristics of a strained by σ 1 − σ 2 KD 2 PO 4 type crystal. Numerical analysis of the obtained results is performed. Stress dependences of the calculated characteristics and the phase diagram are explored. Possibility of the induced by σ 1 − σ 2 phase transition into a new paraelectric phase with monoclinic symmetry is discussed.

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“…Dynamics of hydrogen-bonded ferroelectrics with taking into account tunnelling effects was considered in Refs. [50][51][52] within the proposed in [50] original approach. For the first time it has been shown, that in the reference approach, with the short-range interactions and tunnelling taken into account in cluster approximation, the dynamic properties of the studied systems are to a great extent determined by an effective tunnelling parameter, renormalized by the short-range interactions.…”

Section: Introductionmentioning

confidence: 99%

Reference Approach in Theory of Pseudospin Systems

Левицкий¹,

Sorokov²,

Baran³

2000

Condens. Matter phys.

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For theoretical description of pseudospin systems with essential shortrange and long-range interactions we use the method based on calculations of the free energy functional taking into account the short-range interactions within the reference approach in cluster approximation. We propose a consistent formulation of the cluster expansion method for quantum pseudospin systems. We develop a method allowing one to obtain within the cluster approximation an Ornstein-Zernike type equation for reference cumulant Green function of an arbitrary order. In the two-particle cluster approximation we derived an explicit expression for pair temperature cumulant Green function of the reference system. In the cluster random phase approximation we calculated and studied thermodynamic characteristics, elementary excitation spectrum, and integral intensities of the Ising model in transverse field.

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Dynamics of ferroactive crystals of orthophosphate type

Cited by 8 publications

References 1 publication

Thermodynamics and Dielectric Properties of the Nh_4h_2po_4 Type Antiferroelectrics

Thermodynamics and Dielectric Properties of the Nh_4h_2po_4 Type Antiferroelectrics

INFLUENCE OF sigma_1-sigma_2 STRESS ON PHASE TRANSITION AND PHYSICAL PROPERTIES OF KD_2PO_4-TYPE FERROELECTRICS

Reference Approach in Theory of Pseudospin Systems

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