High-pressure investigation of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>CaTiO</mml:mtext></mml:mrow><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>up to 60 GPa using x-ray diffraction and Raman spectroscopy

Guennou, Maël; Bouvier, Pierre; Krikler, B.; Kreisel, J.; Haumont, R.; Garbarino, Gastón

doi:10.1103/physrevb.82.134101

Cited by 65 publications

(56 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(1) The pressure-induced change in octahedral rotation and tilt dR/dP decreases with increasing Goldshmidt tolerance factor (defined as τ = (r A +r O )/ √ 2(r B +r O ), where r A , r B , r O are radii of the A-, B cations, and O anion) [26,27]. This has explained the pressure behavior in orthorhombic CaSnO 3 [28], CaTiO 3 [29], and SrTiO 3 [30]. (2) Materials with similar τ show increasing dR/dP as they move from…”

Section: Figmentioning

confidence: 94%

Soft antiphase tilt of oxygen octahedra in the hybrid improper multiferroicCa3Mn1.9Ti0.1O7

Wang

Sheng

et al. 2018

Phys. Rev. B

View full text Add to dashboard Cite

We report a single crystal neutron and x-ray diffraction study of the hybrid improper multiferroic Ca3Mn1.9Ti0.1O7 (CMTO), a prototypical system where the electric polarization arises from the condensation of two lattice distortion modes. With increasing temperature (T ), the out-of-plane, antiphase tilt of MnO6 decreases in amplitude while the in-plane, inphase rotation remains robust and experiences abrupt changes across the first-order structural transition. Application of hydrostatic pressure (P ) to CMTO at room temperature shows a similar effect. The consistent behavior under both T and P reveals the softness of antiphase tilt and highlights the role of the partially occupied d orbital of the transition metal ions in determining the stability of the octahedral distortion. Polarized neutron analysis indicates the symmetry-allowed canted ferromagnetic moment is less than 0.04 µB/Mn site, despite a substantial out-of-plane tilt of the MnO6 octahedra.PACS numbers: 75.58.+t,81.40.Vw,61.05.F-Multiferroic compounds with spontaneous elastic, electrical, magnetic orders are considered as the key materials to achieve cross-control between magnetism and electricity in solids with small energy dissipation [1,2]. The functional properties including colossal magnetoelectric effect could be used in solid-state memories and sensors [3]. The desired multifunctional behavior requires common microscopic origin of the long-range order such that one order parameter is strongly coupled to the conjugate field of the other one. So far, the majority of attention has focused on exploring materials with magnetic origin, where the underlying microscopic mechanisms are primarily classified into three types: symmetric spin exchange interaction Σ ij (S i · S j ) [4, 5], antisymmetric spin-exchange interaction S i × S j [6, 7], and spindependent p − d hybridization due to spin-ligand interaction (e il · S i ) 2 e il [8]. The material-by-design efforts focusing on magnetic oxides has been productive; the ferroelectricity is induced either through epitaxial strain engineering or chemical substitution of stereochemical inactive ions with lone-pair-active cations [9,10].However, this approach requires a strong coupling between ferroelectricity and magnetism. The microscopic mechanism with spin origin also implicitly suggests a low operating temperature because of the magnetic frustration. On the other hand, perovskites in the form of ABO 3 and their derivatives are favorably chosen for functional materials due to their high susceptibility toward polar structural instability and the intimate coupling between the ferroelectric polarization and the magnetic, orbital, and electronic degrees of freedom. Recently, a novel mechanism termed as "hybrid improper ferroelectric" has been proposed to search for materials with spontaneous ferroelectricity. The central idea is that the polar mode is driven by the condensation of two nonpolar lattice modes, which represent oxygen octahedral rotation (X + 2 ) and tilt (X − 3 ), respectively [11][12][13]. It i...

show abstract

Section: Figmentioning

confidence: 94%

Soft antiphase tilt of oxygen octahedra in the hybrid improper multiferroicCa3Mn1.9Ti0.1O7

Wang

Sheng

et al. 2018

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…With increasing pressure, the room-temperature Raman spectrum of BaZrO 3 tends to vanish, which was taken as a support for a scenario where locally distortions give space to macroscopically cubic phase [13]. However, a classical second-order spectrum is also expected to decrease in intensity with pressure [47] -as it was observed in SrTiO 3 [48] and CaTiO 3 [49], so that this observation alone is inconclusive.…”

Section: B Low-frequency Spectrummentioning

confidence: 97%

Lattice dynamics and Raman spectrum of BaZrO3 single crystals

et al. 2019

Self Cite

View full text Add to dashboard Cite

BaZrO3 is a perovskite that remains in the simple cubic phase at all temperatures, hence with no first-order Raman-active phonon mode allowed by symmetry. Yet, it exhibits an intense Raman spectrum with sharp and well-defined features. Here, we report the evolution of the Raman spectrum of BaZrO3 single crystals in a broad temperature range (4-1200 K) and discuss its origin with the support of detailed first-principle calculations of the lattice dynamics. Phonon calculations are performed not only for the cubic phase of BaZrO3, but also for the low-symmetry phases with octahedra tilts that have been suspected to exist at the nanoscale. We show that the Raman spectrum shows no direct evidence for these nanodomains, but can instead be explained by classical second-order Raman scattering. We provide an assignment of the dominant features to phonon modes combinations. In particular, we show that the high frequency range of the spectrum is dominated by overtones and shows an image of the phonon density of states corresponding to the stretching modes of the oxygen octahedra.

show abstract

“…Most other materials display fewer phase transitions under pressure: e.g. CaTiO 3 (no transition [47]), SrTiO 3 (one transition [46]), or PbTiO 3 (two transitions [12]). In the light of this, the here observed 6 phase transitions of BiFeO 3 are remarkable.…”

Section: Importance Of Non-hydrostatic Stressmentioning

confidence: 99%

“…The two tilt angles Ti-O1-Ti (α 1 ) and Ti-O2-Ti (α 2 ) that characterize the P nma structure [8] are best determined from the atomic positions obtained by Rietveld refinements, but the quality of our powder data does not allow to determine atomic position with satisfying uncertainties. Tilt angles can also be calculated from the lattice constants under the assumption of undistorted polyhedra [8], but these formulas are known to give only rough estimations of the tilt angles [47]. From these formula and our measured lattice constants, we can estimate that the octahedra tilt angles decrease in the P nma structure by less than 2…”

Section: Importance Of Non-hydrostatic Stressmentioning

confidence: 99%

See 1 more Smart Citation

Multiple high-pressure phase transitions in BiFeO3

et al. 2011

Self Cite

View full text Add to dashboard Cite

We investigate the high-pressure phase transitions in BiFeO3 by single crystal and powder x-ray diffraction, as well as single crystal Raman spectroscopy. Six phase transitions are reported in the 0-60 GPa range. At low pressures, up to 15 GPa, 4 transitions are evidenced at 4, 5, 7 and 11 GPa. In this range, the crystals display large unit cells and complex domain structures, which suggests a competition between complex tilt systems and possibly off-center cation displacements. The non polar P nma phase remains stable over a large pressure range between 11 and 38 GPa, where the distortion (tilt angles) changes only little with pressure. The two high-pressure phase transitions at 38 and 48 GPa are marked by the occurence of larger unit cells and an increase of the distorsion away from the cubic parent perovskite cell. We find no evidence for a cubic phase at high pressure, nor indications that the structure tends to become cubic. The previously reported insulator-to-metal transition at 50 GPa appears to be symmetry breaking.

show abstract

High-pressure investigation ofCaTiO3up to 60 GPa using x-ray diffraction and Raman spectroscopy

Cited by 65 publications

References 56 publications

Soft antiphase tilt of oxygen octahedra in the hybrid improper multiferroicCa3Mn1.9Ti0.1O7

Soft antiphase tilt of oxygen octahedra in the hybrid improper multiferroicCa3Mn1.9Ti0.1O7

Lattice dynamics and Raman spectrum of BaZrO3 single crystals

Multiple high-pressure phase transitions in BiFeO3

Contact Info

Product

Resources

About