Phase Transitions in Lead Hafnate under High Pressure

Knyazeva, M. A.; Andronikova, Daria; Lityagin, Georgiy; Bronwald, Iurii; Paraskevas, P.; Majchrowski, A.; Roleder, Krystian; Filimonov, A. V.; Burkovsky, R. G.

doi:10.1134/s1063783419100202

Cited by 14 publications

(14 citation statements)

References 28 publications

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Section: Introductionmentioning

confidence: 52%

“…On the phase diagram included one can see that for the PHSx (PbHf 1−x Sn x O 3 ) compounds with x > 0.06, the existence of another IM, similar to that observed in 20 under the high-pressureβ phase, was detected. In 20 it is stated that this β phase in PbHfO 3 may be similar to one recently reported as the high-pressure-high-temperature phase observed in PZO. 8 Although the influence of hydrostatic pressure on PHO structure seems to be quite well documented in the literature, the influence of Sn ions exerting chemical pressure on the structural properties of PHS solid solutions is still not properly understood.…”

Section: Introductionmentioning

confidence: 52%

“…On the other hand, it was also shown that these two distortions may be separated at elevated hydrostatic pressure. 20 In our studies, we noticed that isovalent doping of PHO by Sn ions (forming solid solution) produces effects similar to those of the hydrostatic pressure. [21][22][23][24][25] It is due to the fact that in PHS, a larger Hf 4+ ion (r = 0.71 Å) is replaced by a smaller Sn 4+ ion (r = 0.67 Å) in the central position in oxygen octahedra.…”

Section: Introductionmentioning

confidence: 55%

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The complexity of structural phase transitions in Pb(Hf_0.92Sn_0.08)O₃ single crystals

Jankowska‐Sumara

Majchrowski

2021

J. Am. Ceram. Soc.

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Pb(Hf 1−x Sn x )O 3 single crystals with x = 0.08 were characterized using single-crystal X-ray diffraction and Raman scattering, in a wide temperature range. The information concerning the structure of two intermediate phases (IMs), situated between lowtemperature antiferroelectric A1 and high-temperature paraelectric PE phases, was obtained. The lower temperature IM, A2, is characterized by incommensurate displacive modulations in the Pb sublattice. The higher temperature IM, is characterized by tilting of oxygen octahedra, and serious disorder coming from lead ions represented by X-ray diffuse scattering. Optical phonons and phase transitions in Pb(Hf 1−x Sn x ) O 3 single crystals were investigated by temperature-dependent Raman spectra. It was found that several soft modes control the phase transition between two antiferroelectric phases indicating its displacive character, whereas, in the paraelectric phase, both soft modes and Rayleigh scattering were observed.

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Section: Introductionmentioning

confidence: 52%

Section: Introductionmentioning

confidence: 52%

Section: Introductionmentioning

confidence: 55%

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The complexity of structural phase transitions in Pb(Hf_0.92Sn_0.08)O₃ single crystals

Jankowska‐Sumara

Majchrowski

2021

J. Am. Ceram. Soc.

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“…This phase is of lowerthan-cubic symmetry, has an additional order parameter (octahedral tilts, as Ref. [42] suggests), apparently no long-range ordered displacements in cation subsystem, but strong fluctuations of inhomogeneous polarization, as seen by diffuse scattering. It would be seen as a good model object, but studying it in temperature domain is difficult, since pressure complicates such experiments considerably.…”

Section: B Motivationmentioning

confidence: 77%

“…A natural test ground for this could be the highpressure intermediate phase in PbZrO 3 [13,41] and PbHfO 3 [41,42] that becomes stable between the cubic and the incommensurate phases almost immediately on raising pressure above ambient. This phase is of lowerthan-cubic symmetry, has an additional order parameter (octahedral tilts, as Ref.…”

Section: B Motivationmentioning

confidence: 99%

Ferroelectric to incommensurate fluctuations crossover in PbHfO3-PbSnO3

Kniazeva,

Ganzha,

Jankowska-Sumara

et al. 2021

Preprint

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A. Models of antiferroelectricsComplexity of antiferroelectrics resulted in a rather large number of different approaches and perspectives in their modeling. To help the reader navigate that, a brief systematization follows.First model of antiferroelectrics is due to Kittel [1], who reduced an (at that time -abstract) antiferroelectric to two inter-penetrating lattices with anti-parallel polarizations. The most studied real antiferroelectric, PbZrO 3 , is much more complex than that, in part -due to the more complex dipole ordering ↑↑↓↓ [24], due to the possibility of alternative incommensurate orderings [9] and due to the presence of anti-phase octahedral tilts as a second type of distortion [24], usually coexisting with the anti-polar ordering of cations.Modern models fall, roughly, into three categories. First -ab-initio analysis [25][26][27] of energy landscape at zero Kelvin, sometimes extended to modeling of finite temperature behavior via molecular dynamics [22,28,29]. Usually this extension needs a parametrization of energy in terms of local ionic displacements around

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Effect of Sn Addition on Thermodynamic, Dielectric, Optical, and Acoustic Properties of Lead Hafnate

Piekara

Lee

et al. 2020

Physica Status Solidi (a)

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Specific heat, dielectric properties, domain structure, and Brillouin light scattering studies in antiferroelectric PbHf1−xSnxO3 single crystals with three different concentrations (x = 0.08, 0.1, and 0.23) are performed in function of temperature. The specific heat and dielectric data reveal clear anomalies at three temperatures denoted as T1, T2, and TC. At T1, transition from the antiferroelectric AFE1 to another antiferroelectric AFE2 phase is realized, the next phase transition (PT) is from AFE2 to an intermediate (IM) phase—at T2, and from IM to paraelectric (PE) phase at TC. PTs at T1 and T2 are definitely of the first order, whereas the PT at TC has features of the second‐order PT. The PT sequences are confirmed by changes in the domain structure. In the PE phase, Brillouin studies reveal the softening and broadening of longitudinal acoustic (LA) mode in the cooling process. The softening and broadening exhibit the maximum values near TC. The transverse acoustic (TA) mode appears near T2. Additional acoustic anomalies are also observed at T1. The temperature dependencies of LA mode indicate the existence of polar regions in PE phase and order–disorder character of the PT at TC. The other PTs are mainly of a displacive character.

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Phase Transitions in Lead Hafnate under High Pressure

Cited by 14 publications

References 28 publications

The complexity of structural phase transitions in Pb(Hf_0.92Sn_0.08)O₃ single crystals

The complexity of structural phase transitions in Pb(Hf_0.92Sn_0.08)O₃ single crystals

Ferroelectric to incommensurate fluctuations crossover in PbHfO3-PbSnO3

Effect of Sn Addition on Thermodynamic, Dielectric, Optical, and Acoustic Properties of Lead Hafnate

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Phase Transitions in Lead Hafnate under High Pressure

Cited by 14 publications

References 28 publications

The complexity of structural phase transitions in Pb(Hf0.92Sn0.08)O3 single crystals

The complexity of structural phase transitions in Pb(Hf0.92Sn0.08)O3 single crystals

Ferroelectric to incommensurate fluctuations crossover in PbHfO3-PbSnO3

Effect of Sn Addition on Thermodynamic, Dielectric, Optical, and Acoustic Properties of Lead Hafnate

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The complexity of structural phase transitions in Pb(Hf_0.92Sn_0.08)O₃ single crystals

The complexity of structural phase transitions in Pb(Hf_0.92Sn_0.08)O₃ single crystals