The influence of hydrostatic pressure p_h and shear stress σ₅ on the phase transitions and thermodynamics of the RbHSO₄ ferroelectrics

Abstract

Отримано 06 травня 2015 р.; в остаточному виглядi 03 липня 2015 р.)Використано модифiковану чотирипiдґраткову модель RbHSO4 врахуванням п'єзоелектричного зв'язку з деформацiями εi, εj. У наближеннi молекулярного поля розраховано компоненти вектора поляризацiї та тензора статичної дiелектричної проникностi механiчно затиснутого й вiльного кристалiв, їх п'єзоелектричнi характеристики. Дослiджено вплив гiдростатичного тиску та зсувної напруги на фазовий перехiд i фiзичнi характеристики кристала. Отримано добрий кiлькiсний опис вiдповiдних експериментальних даних для цих кристалiв.Ключовi слова: сеґнетоелектрики, температура переходу, дiелектрична проникнiсть, п'єзомодулi, гiдростатичний тиск, напруга зсуву.

Deformation effects in glycinium phosphite ferroelectric

“…Following the publication of papers [18][19][20][21][22][23][24] in [25], the piezoelectric coupling was taken into account during the study of the effect of hydrostatic pressure on the physical characteristics of KH 2 PO 4 type crystals. Later on, within the models of deformed ferroelectric crystals, the investigations of the effect of hydrostatic pressure on the phase transition and on the physical characteristics of quasionedimensional CsH 2 PO 4 type ferroelectrics [26], monoclinic RbD 2 PO 4 [27], as well as RbHSO 4 [28] were also carried out.…”

Influence of uniaxial pressures on dynamic dielectric characteristics of RbHSO4

“…This model permitted to obtain a qualitatively correct description of the elastic constants, and a quantitatively correct description of the static and dynamic dielectric and thermal properties of this crystal; in [5] the dielectric properties of deuterated RbDSO 4 have been successfully described by the same model. The influence of hydrostatic pressure on the phase transition and longitudinal dielectric permittivity of RbHSO 4 were explored [6]; an attempt to predict the effects of the uniaxial pressures and the shear stress σ 5 on the dielectric permittivity was made in [6,7]. However, the model [4] does not take into account the splitting of the parameters of interactions between the pseudospins in presence of the shear strains ε 4 or ε 6 ; hence, no reliable prediction of the shear stresses σ 4 or σ 6 effects on the thermodynamic characteristics can be made within its framework.…”

The effect of hydrostatic pressure on thermodynamic characteristics of NH3CH2COOH·H2PO3 type ferroelectric materials

“…It is necessary to note that an acceptable description of an external hydrostatic pressure effect on the phase transition and physical characteristics for many ferroelectric crystals of KH 2 PO 4 family was made in [1,2], for quasione-dimentional CsH 2 PO 4 type ferroelectrics -in [3], for monoclinic RbD 2 PO 4in [4], for RbH 2 SO 4 crystal -in [5].…”