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1

Manifestation of a Coexistence of the Long-Periodic Phase with the Incommensurate Phase

100%

Sveleba S., Polovinko I., Zhmurko V., Pankivskyi Y.

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vol. 96

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issue 3-4

437-444

EN

Electric and optical properties of the commensurate ferroelectric long-periodic phase in [N(CH_{3})_{4}]_{2}ZnCl_{4} and [N(CH_{3})_{4}]_{2}CoCl_{4} crystals were investigated to explain mechanism of the double hysteresis loops appearance.

2

Influence of Mechanical Stress on the Birefringence Properties of (N(CH_{3})_{4})_{2}ZnCl_{4} Crystals

100%

Polovinko I., Sveleba S., Vlokh O., Zhmurko V.

Acta Physica Polonica A

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1992

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vol. 81

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issue 3

409-412

EN

The influence of applied mechanical stress on the birefringence of (N(CH_{3})_{4})_{2}ZnCl_{4} crystal in the temperature region of its incommensurate phase was investigated using Senarmonth's method (λ = 633 nm). The value of pinning force for the samples with different defectiveness was experimentally determined.

3

Optical and Ultrasonic Investigations of Phase Transitions in Ferroelectric RbHSeO_{4} Single Crystal

76%

Sveleba S., Bublik M., Polovinko I., Kityk A., Sopronuk V., Czapla Z.

Acta Physica Polonica A

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1992

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vol. 82

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issue 3

481-486

EN

Birefringence and ultrasonic measurements were done for ferroelectric RbHSeO4 crystal. Influences of both stresses (σ_{i}) and pressure on the properties and phase transition were studied as well. The observed dependence of δ(Δn_{b}) = f(σ_{5}) shows hysteresis loop characteristic of ferroelectric phase whereas the dependence of δ(Δn_{c}) = f(σ_{6}) shows hysteresis loop characteristic of ferroelastic phase. Birefringence measurements prove the phase transition to ferroelectric phase at 373 K. Additionally, the phase transition was found at 398 K. The new phase may be regarded as an incommensurate one. On the grounds of the stresses influence the phase diagram is constructed in coordinates T, σ_{5}. The linear decrease in T_{c} with increase in pressure is observed in ultrasonic studies and it is similar to the results obtained in DSC measurements.

4

Birefringent and Dielectric Properties of [N(C_{2}H_{5})_{4}]_{2}ZnBr_{4} and [N(C_{2}H_{5})_{4}]_{2}CdBr_{4} Crystals

64%

Sveleba S., Mokryi V., Polovinko I., Kapustyanik V., Trybuła Z., Petrenko P., Kiosse G., Kravtsov V.

Acta Physica Polonica A

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1993

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vol. 83

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issue 6

777-784

EN

Dielectric and birefringent properties of [N(C_{2}H_{5})_{4}]_{2}ZnBr_{4} and [N(C_{2}H_{5})_{4}]_{2}CdBr_{4} crystals were investigated. It has been ascertained that two phase transitions manifest themselves in the temperature dependencies є(T) for [N(C_{2}H_{5})_{4}]_{2}CdBr_{4} crystal - a second-order transition at T_{1} = 311 K and a first-order one - at T_{2} = 39 K (∆T_{2} = 11 K). Besides two earlier known phase transitions in [N(C_{2}H_{5})_{4}]_{2}ZnBr_{4} at T_{1} = 350 K and T^{cool}_{2} = 282.8 K (∆T_{2} ≈ 2.3 K), the additional one was found at T*_{2} = 287.0 K, both on the cooling and heating runs. On the basis of the data about the peculiarities of dielectric and optical properties in the vicinity of T_{2} one can made the conclusion about the ferroelectric character of the phase, situated between T*_{2} and T^{cool}_{2}.

Refine search results

4 Acta Physica Polonica A

1 1999

1 1993

2 1992

4 Polovinko I.

4 Sveleba S.

2 Zhmurko V.

1 Bublik M.

1 Czapla Z.

1 Kapustyanik V.

1 Kiosse G.

1 Kityk A.

1 Kravtsov V.

1 Mokryi V.

1 Pankivskyi Y.

1 Petrenko P.

1 Sopronuk V.

1 Trybuła Z.

1 Vlokh O.

Manifestation of a Coexistence of the Long-Periodic Phase with the Incommensurate Phase

Influence of Mechanical Stress on the Birefringence Properties of (N(CH_{3})_{4})_{2}ZnCl_{4} Crystals

Optical and Ultrasonic Investigations of Phase Transitions in Ferroelectric RbHSeO_{4} Single Crystal

Birefringent and Dielectric Properties of [N(C_{2}H_{5})_{4}]_{2}ZnBr_{4} and [N(C_{2}H_{5})_{4}]_{2}CdBr_{4} Crystals