An intermediate antipolar phase in NaNbO<sub>3</sub> under compression

Кичанов, С. Е.; Козленко, Д. П.; Belozerova, N. M.; Jabarov, S. H.; Mehdiyeva, R. N.; Лукин, Е. В.; Mammadov, A. I.; Liermann, Hanns‐Peter; Morgenroth, Wolfgang; Dubrovinsky, Leonid; Савенко, Б. Н.; Raevski, I. P.; Dang, N. T.

doi:10.1080/00150193.2017.1374801

Cited by 13 publications

(6 citation statements)

References 29 publications

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“…The bulk modulus value of the pressure-induced B2cb phase of Bi 2 WO 6 is noticeably larger than that for the ambient-pressure phase P2 1 ab, and it is close to the values obtained for the highpressure phase of BiMn 2 O 5 (B 0 = 167 GPa; Pandey et al, 2013;Dang et al, 2017), the high-pressure cubic phase of Pb 2 MgWO 6 (B 0 = 169 GPa;Mekhdieva et al, 2014) and the cubic phase of BaTiO 3 (B 0 = 147 GPa;Jabarov et al, 2017). At the same time, the compressibility of the ambient-pressure phase of Bi 2 WO 6 is comparable with the values obtained for the antiferroelectric phase of NaNbO 3 (B 0 = 132 GPa;Kichanov et al, 2017) and the orthorhombic phase of Bi 2 MoO 6 (B 0 = 51 GPa;Scott et al, 2012).…”

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confidence: 52%

Pressure-induced structural phase transitions in bismuth tungstate Bi₂WO₆

Lis¹,

Кичанов²,

Козленко³

et al. 2021

Acta Crystallogr Sect B

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The pressure-induced structural phase transitions in bismuth tungstate Bi2WO6 have been studied using neutron diffraction and Raman spectroscopy at high pressures up to 7 and 30 GPa, respectively. A rich structural polymorphism was revealed. At P ≃ 3.5 GPa a phase transition from the initial orthorhombic phase of P21 ab symmetry to an orthorhombic phase of B2cb symmetry was observed. This transition is caused by the complex spatial rotation of the WO6 octahedra. A subsequent isostructural phase transition to another orthorhombic phase of B2cb symmetry was detected at P ≃ 5.9 GPa, accompanied by changes in both the mutual rotation and tilting of the oxygen octahedra with respect to the crystal b axis. Two more pressure-induced phase transitions in Bi2WO6 at high pressures of 11.5 and 20 GPa were observed in the Raman spectra. These pressure-driven phase transitions in bismuth tungstate are accompanied by anomalies in the pressure dependences of the unit-cell parameters, bond lengths and angles, and in the vibrational modes.

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mentioning

confidence: 52%

Pressure-induced structural phase transitions in bismuth tungstate Bi₂WO₆

Lis¹,

Кичанов²,

Козленко³

et al. 2021

Acta Crystallogr Sect B

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“…Neutron diffraction also revealed changes in the baric behaviour of Nb-O-Nb bond angles as a result of complex reorientations of NbO 6 octahedra at high pressures of ~2 GPa [19]. Recent, high pressure X-ray diffraction data suggest that the paraelectric (Pbnm) phase is stable up to 30 GPa [29].…”

Section: Introductionmentioning

confidence: 98%

High-Pressure Vibrational and Structural Studies of the Chemically Engineered Ferroelectric Phase of Sodium Niobate

Mishra,

Garg,

Gohil

et al. 2023

Crystals

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Pure NaNbO3 has an antiferroelectric phase at ambient pressure. The structural behaviour of the chemically engineered ferroelectric phase of sodium niobate, NNBT05: [(0.95) NaNbO3-(0.05) BaTiO3], under high-pressure has been studied using Raman scattering and angle-dispersive synchrotron X-ray diffraction techniques. At pressure > 1 GPa, noticeable changes in the Raman spectra can be seen in the low wavenumber modes (150–300 cm−1). Large changes in the positions and intensities of the Raman bands as a function of pressure provide evidence for structural phase transition. The results indicate significant changes in the bond-lengths and the orientation of the NbO6 octahedra at ~1 GPa, and a transition to the paraelectric phase at ~5 GPa, which are at lower pressures than previously found in pure NaNbO3. The powder X-ray diffraction pattern shows an appreciable change in the peak profile in terms of position and width on increasing pressure. The pressure dependences of the structural parameters show that the response of the lattice parameters to pressure is strongly anisotropic. By fitting the pressure–volume data using the Birch–Murnaghan equation of state, the isothermal bulk modulus was estimated. The experimental results suggest that on doping BaTiO3 in NaNbO3, the bulk modulus increases. The bulk modulus of NNBT05 has been estimated to be 164.5 GPa, which is fairly close to 157.5 GPa, as previously observed in NaNbO3.

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“…В сложных оксидах могут наблюдаться различные фазовые переходы. Сегнетоэлектрические-параэлектрические и ферромагнитные-парамагнитные фазовые переходы в этих материалах широко исследуются [6][7][8][9]. Среди сложных оксидов нитраты занимают особое место.…”

Section: Introductionunclassified

Кинетика IV -> III полиморфного превращения в монокристаллах Rb-=SUB=-1-x-=/SUB=-Cs-=SUB=-x-=/SUB=-NO-=SUB=-3-=/SUB=- (x=0.025, 0.05, 0.1)

Хазиева¹,

Насиров²,

Алыев³

et al. 2022

Физика И Техника Полупроводников

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Методом оптической микроскопии измерена скорость роста кристаллов III-модификации от температуры при превращении IV -> III в монокристаллах Rb1-xCsxNO3 (x=0.025, 0.05, 0.1). Показано, что скорость роста кристаллов III-модификации в зависимости от температуры при превращении IV -> III описывается эмпирической формулой IV->III=(-0.486Delta T+0.592Delta T2 -0.0015Delta T3)·10-2 см/с для x=0.025, IV-> III=(-0.49Delta T+0.563Delta T2-0.0018Delta T3)·10-2 см/с для x=0.005 и IV->III= (-0.437Delta T+0.484Delta T2-0.0014Delta T3)·10-2см/с для x=0.1, где Delta T=Ttr+T0. Вычислена энергия активации процесса IV -> III превращения, которая равна E=85.5 кДж/моль для x=0.025, E=82.8 кДж/моль для x=0.005 и E=84.8 кДж/моль для x=0.1. Ключевые слова: кристаллы, полиморфные превращения, энергия активации.

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An intermediate antipolar phase in NaNbO₃ under compression

Cited by 13 publications

References 29 publications

Pressure-induced structural phase transitions in bismuth tungstate Bi₂WO₆

Pressure-induced structural phase transitions in bismuth tungstate Bi₂WO₆

High-Pressure Vibrational and Structural Studies of the Chemically Engineered Ferroelectric Phase of Sodium Niobate

Кинетика IV -> III полиморфного превращения в монокристаллах Rb-=SUB=-1-x-=/SUB=-Cs-=SUB=-x-=/SUB=-NO-=SUB=-3-=/SUB=- (x=0.025, 0.05, 0.1)

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An intermediate antipolar phase in NaNbO3 under compression

Cited by 13 publications

References 29 publications

Pressure-induced structural phase transitions in bismuth tungstate Bi2WO6

Pressure-induced structural phase transitions in bismuth tungstate Bi2WO6

High-Pressure Vibrational and Structural Studies of the Chemically Engineered Ferroelectric Phase of Sodium Niobate

Кинетика IV -&gt; III полиморфного превращения в монокристаллах Rb-=SUB=-1-x-=/SUB=-Cs-=SUB=-x-=/SUB=-NO-=SUB=-3-=/SUB=- (x=0.025, 0.05, 0.1)

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An intermediate antipolar phase in NaNbO₃ under compression

Pressure-induced structural phase transitions in bismuth tungstate Bi₂WO₆

Pressure-induced structural phase transitions in bismuth tungstate Bi₂WO₆

Кинетика IV -> III полиморфного превращения в монокристаллах Rb-=SUB=-1-x-=/SUB=-Cs-=SUB=-x-=/SUB=-NO-=SUB=-3-=/SUB=- (x=0.025, 0.05, 0.1)