Lattice dynamic investigation of the phonon wavenumbers of CaGeO3 perovskite

Gupta, H.C.; Ashdhir, P.

doi:10.1002/(sici)1097-4555(199906)30:6<493::aid-jrs401>3.0.co;2-y

Cited by 5 publications

(1 citation statement)

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“…Information can nonetheless be gained from comparison with Raman data and simulations of isostructural CaBO 3 perovskites. Several such perovksites have been studied in the past for B = Ge, Sn, Zr, Mn [43,[47][48][49]. All of them have the P nma orthorhombic structure and the distortion from the cubic perovskite in CTO, as measured for example by the tilt angles, is intermediate between CaGeO 3 and CaMnO 3 .…”

Section: Raman Spectroscopymentioning

confidence: 99%

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

et al. 2010

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In this work, we investigate calcium titanate (CaTiO3 -CTO) using X-ray diffraction and Raman spectroscopy up to 60 and 55 GPa respectively. Both experiments show that the orthorhombic P nma structure remains stable up to the highest pressures measured, in contradiction to ab-initio predictions. A fit of the compression data with a second-order Birch-Murnaghan equation of state yields a bulk modulus K0 of 181.0(6) GPa. The orthorhombic distortion is found to increase slightly with pressure, in agreement with previous experiments at lower pressures and the general rules for the evolution of perovskites under pressure. High-pressure polarized Raman spectra also enable us to clarify the Raman mode assignment of CTO and identify the modes corresponding to rigid rotation of the octahedra, A-cation shifts and Ti-O bond stretching. The Raman signature is then discussed in terms of compression mechanisms.

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Section: Raman Spectroscopymentioning

confidence: 99%

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

et al. 2010

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Force constant calculation from Raman and IR spectra in the three non‐cubic phases of BaCeO₃

Gupta¹,

Simon²,

Pagnier³

et al. 2001

J Raman Spectroscopy

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Raman spectroscopic data for BaCeO 3 were modeled with the use of a small set of force constants in its three phases (Pnma, Imma and R3c) using experimental IR and Raman data. An IR reflectance spectrum of BaCeO 3 in its Pnma phase is provided for the first time. Raman band symmetry assignments in the Pnma phase were re-examined and the assignments of Genet et al. were confirmed. The distribution of the Raman bands of the Pnma phase between the zone center and X point in Imma is provided and band assignments were extended to the Imma and R3c phases. Calculated values for both Raman-and IR-active modes are provided in the three phases. The variations in force constants throughout the phase transitions are briefly discussed.

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Phonon behavior of CaSnO3 perovskite under pressure

Kung

Lin

2011

The Journal of Chemical Physics

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Raman scattering and x-ray diffraction studies of CaSnO(3) perovskite were performed under high-pressure conditions. This high-pressure study was motivated by a recent theoretical study predicting a phase transition in CaSnO(3) from GdFeO(3)-type perovskite to CaIrO(3)-type structure occurred at 12 GPa. Despite no obvious structure change up to a pressure of 26 GPa based on the x-ray diffraction data, high pressure Raman measurements revealed that some Raman modes disappeared upon compression; either merging into neighboring bands or vanishing. The signals for these Raman peaks were recovered during decompression. The measured pressure derivative of Raman shift (∂ν∕∂P) of CaSnO(3) ranged from ~1.29 to ~4.35, up to 20 GPa. Due to the lack of lattice dynamic study for CaSnO(3) perovskite, the mode symmetry for CaSnO(3) was tentatively assigned based on the empirical relation among Ca-bearing perovskites. The pressure derivative of the Raman shifts was found to be related to their mode vibrations: modes related to Ca and O shifts had a strong pressure dependence compared with those associated with oxygen octahedral rotation.

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Lattice dynamic investigation of the phonon wavenumbers of CaGeO3 perovskite

Cited by 5 publications

References 4 publications

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

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

Force constant calculation from Raman and IR spectra in the three non‐cubic phases of BaCeO₃

Phonon behavior of CaSnO3 perovskite under pressure

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Lattice dynamic investigation of the phonon wavenumbers of CaGeO3 perovskite

Cited by 5 publications

References 4 publications

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

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

Force constant calculation from Raman and IR spectra in the three non‐cubic phases of BaCeO3

Phonon behavior of CaSnO3 perovskite under pressure

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Force constant calculation from Raman and IR spectra in the three non‐cubic phases of BaCeO₃