Atomistic mechanism leading to complex antiferroelectric and incommensurate perovskites

Patel, Kinnary; Prosandeev, S. A.; Yang, Yurong; Xu, Bin; Íñiguez, Jorgé; Bellaïche, L.

doi:10.1103/physrevb.94.054107

Cited by 26 publications

(35 citation statements)

References 34 publications

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“…It is interesting to note the condensation of the q 2 = 1 / 2 [111] p * mode at high temperature. The simultaneous reappearance of the octahedral rotation and the antiparallel ionic displacements further supports the fact that the strong coupling between the AFE and AFD modes contributes to the AFE structure and the antiferroelectricity described by the first-principles calculation [17].…”

Section: B Temperature-induced Phase Transitionsupporting

confidence: 64%

“…In reality, the AFE-FE transition is considerably more complicated. Recently, the origin of antiferroelectricity in PZO and PZO-related materials has been under intensive discussion, particularly from the soft mode and overall energy points of view [13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

“…Theoretical calculations [14,17] suggest the collaborative coupling between the A-site ionic displacements, q 1 , and the octahedral rotation, q 2 , mode(s) that can lead to "hybrid normal modes," which can explain the experimental fact that both modes condense simultaneously at a certain temperature in the case of PZO as well as the existence of a soft phonon branch along the γ [110] p * reciprocal space direction. The calculations [14,31] also point out that the coupling between the AFD mode and the FE mode is present in a competitive rather than a collaborative nature.…”

Section: Introductionmentioning

confidence: 99%

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Critical role of the coupling between the octahedral rotation andA-site ionic displacements inPbZrO3-based antiferroelectric materials investigated byin situneutron diffraction

Lü

Studer

et al. 2017

Phys. Rev. B

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This in situ neutron-diffraction study on antiferroelectric (AFE) Pb 0.99 (Nb 0.02 Zr 0.65 Sn 0.28 Ti 0.05)O 3 polycrystalline materials describes systematic structural and associated preferred orientation changes as a function of applied electric field and temperature. It is found that the pristine AFE phase can be poled into the metastable ferroelectric (FE) phase at room temperature. At this stage, both AFE and FE phases consist of modes associated with octahedral rotation and A-site ionic displacements. The temperature-induced phase transition indicates that the octahedral rotation and ionic displacements are weakly coupled in the room-temperature FE phase and decoupled in the high-temperature FE phase. However, both temperature and E-field-induced phase transitions between the AFE and high-temperature FE phase demonstrate the critical role of coupling between octahedral rotation and A-site ionic displacements in stabilizing the AFE structure, which provides not only experimental evidence to support previous theoretical calculations, but also an insight into the design and development of AFE materials. Moreover, the associated preferred orientation evolution in both AFE and FE phases is studied during the phase transitions. It is found that the formation of the preferred orientation can be controlled to tune the samples' FE and AFE properties.

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Section: B Temperature-induced Phase Transitionsupporting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Critical role of the coupling between the octahedral rotation andA-site ionic displacements inPbZrO3-based antiferroelectric materials investigated byin situneutron diffraction

Lü

Studer

et al. 2017

Phys. Rev. B

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“…It is also worthwhile to realize that the present work and model most likely are not fully applicable to PbZrO 3 (which is often considered to be the prototype of antiferroelectrics), even if a trilinear energy coupling has been documented there as well. 37,38 This is because it was recently proposed 39 that the unusual Pbam ground state of PbZrO 3 arises from an original bilinear coupling between antipolar motions and oxygen octahedral tiltings. As a result, Eqs.…”

Section: Discussionmentioning

confidence: 99%

Dynamics of antipolar distortions

2017

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Materials possessing antipolar cation motions are currently receiving a lot of attention because they are fundamentally intriguing while being technologically promising. Most studies devoted to these complex materials have focused on their static properties or on their zone-center phonons. As a result, some important dynamics of antipolar cation distortions, such as the temperature behavior of their phonon frequencies, have been much less investigated, despite the possibility to exhibit unusual features. Here, we report the results and analysis of atomistic simulations revealing and explaining such dynamics for BiFeO 3 bulks being subject to hydrostatic pressure. It is first predicted that cooling such material yields the following phase transition sequence: the cubic paraelectric Pm3m state at high temperature, followed by an intermediate phase possessing long-range-ordered in-phase oxygen octahedral tiltings, and then the Pnma state that is known to possess antipolar cation motions in addition to in-phase and antiphase oxygen octahedral tiltings. Antipolar cation modes are found to all have high phonon frequencies that are independent of temperature in the paraelectric phase. On the other hand and in addition to antipolar cation modes increasing in number, some phonons possessing antipolar cation character are rather soft in the intermediate and Pnma states. Analysis of our data combined with the development of a simple model reveals that such features originate from a dynamical mixing between pure antipolar cation phonons and fluctuations of oxygen octahedral tiltings, as a result of a specific trilinear energetic coupling. The developed model can also be easily applied to predict dynamics of antipolar cation motions for other possible structural paths bringing Pm3m to Pnma states.

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“…As physical properties of composites materials depend on interfacial characteristics occurred between its constituents [22][23][24], dielectric measurements allowed probing their characteristics by evaluating the strength of the interfacial polarization effect. The latter arises in heterogeneous systems due to the accumulation of charges at the interface of the constituents.…”

Section: Introductionmentioning

confidence: 99%

Effect of Alfa fiber mechanical separation on dielectric properties of hybrid unsaturated polyester composites

et al. 2018

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An exhaustive study of dielectric and impedance analysis on two Alfa‐fiber‐reinforced unsaturated polyester hybrid composites was performed. Alfa fiber reinforcements were hybridized by wool and PE/PET fibers in the relative volume fraction ratio 17:2:1. However, these reinforcements differ by the number of mechanical separation of Alfa fibers in the Shirley analyzer. For Composite (1), Alfa fibers were separated mechanically once in the Shirley analyzer whereas for the Composite (2), they were separated mechanically twice in the Shirley analyzer. Dielectric parameters analysis (ɛ′, ɛ″) revealed the presence of the α‐relaxation process at intermediate temperature range for the matrix and the water dipoles polarization at low temperatures for the Composite (1). No dynamic dielectric relaxation was observed for the Composite (2) at low temperatures. However, dielectric properties were controlled by the dc conductivity effect at higher temperatures. The Kramers‐Kronig relation was used to eliminate its effect. Hence, α mode relaxation was observed for the matrix and the interfacial polarization effect was observed for its composites. The attenuated effect of this latter for the Composite (2) was attributed to its homogeneous structure. Electrical conductivity analysis using the Jonscher law allowed determining the transport mechanism for all studied materials and confirmed such result. Complex impedance analysis supported the homogeneous structure for the Composite (2). POLYM. COMPOS., 40:1774–1785, 2019. © 2018 Society of Plastics Engineers

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Atomistic mechanism leading to complex antiferroelectric and incommensurate perovskites

Cited by 26 publications

References 34 publications

Critical role of the coupling between the octahedral rotation andA-site ionic displacements inPbZrO3-based antiferroelectric materials investigated byin situneutron diffraction

Critical role of the coupling between the octahedral rotation andA-site ionic displacements inPbZrO3-based antiferroelectric materials investigated byin situneutron diffraction

Dynamics of antipolar distortions

Effect of Alfa fiber mechanical separation on dielectric properties of hybrid unsaturated polyester composites

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