A High-Pressure Raman Study of Mixed Perovskites BaCexZr1−xO3 (0≤x≤1)

Contin‐Bordes, Cécile; Rosman, N.; Pagnier, Thierry; Lucazeau, G.

doi:10.1006/jssc.1999.8530

Cited by 69 publications

(105 citation statements)

References 20 publications

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“…The observed Raman spectrum is assigned to have its source in the nanodomains with the symmetry different than cubic one. Similar results were presented by Lucazeau [16] and Chemarin et al [17] for BaZrO 3 . The authors showed that these nanodomains are very sensitive to the changes of high pressure.…”

Section: Doping Distortions and Electronic Defectssupporting

confidence: 90%

“…4c when the temperature increases, the local symmetry evolves continuously towards the cubic one. This result is similar to that obtained for BaZrO 3 as the function of high pressure [16,17]. Additional, this fits well with the phase transition determined in the thermal expansion measurements, close to 200…”

Section: Nanoregions In the Pmn-pt Crystals And Ceramicssupporting

confidence: 89%

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Raman Intensity: An Important Tool in the Study οf Nanomaterials and Nanostructures

Colomban

Slodczyk

2009

Acta Phys. Pol. A

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Analysis of the relative and absolute Raman intensity is very important and powerful tool which allows to understand and characterize the modifications of the crystal/amorphous structure due to: (i) changes of the symmetry, e.g. substitution of the B site ion by the rare earth/lanthanide one and incorporation of mobile species in the case of high temperature protonic conducting perovskites; (ii) changes of the short/long range order, e.g. existence/disappearance of the nanoregions in the case of PbMg 1/3 Nb 2/3 O 3−x PbTiO 3 (PMN-PT) relaxor ferroelectric perovskites; (iii) changes of the nanostructure, e.g. depolymerisation of the Si-O network due to the substitution of the Si 4+ ions (and associated covalent bonds) by the M + cations (forming ionic bonds) or by the incorporation of the metal nanoprecipitates in the case of glasses, glazes and enamels.

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Section: Doping Distortions and Electronic Defectssupporting

confidence: 90%

Section: Nanoregions In the Pmn-pt Crystals And Ceramicssupporting

confidence: 89%

Raman Intensity: An Important Tool in the Study οf Nanomaterials and Nanostructures

Colomban

Slodczyk

2009

Acta Phys. Pol. A

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“…Attempt to derive a polyhedral compressibility from spectra in Hazen's model As stated above, Eqn (27) was considered potentially useful for estimating the compressibility of structural units. Hazen's model 23 considers only first-neighbour interactions.…”

Section: Pressure Dependence Of Force Constantsmentioning

confidence: 99%

Effect of pressure and temperature on Raman spectra of solids: anharmonicity

Lucazeau

2003

J Raman Spectroscopy

270

222

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This paper gives a brief review of the effect of temperature and pressure on Raman spectra. Anharmonicity, defined by the cubic, quartic and higher terms in the potential expansion, is shown to be responsible for various properties such as dilatation or for variations of wavenumber and half-width of Raman bands with temperature and pressure, or may be strongly involved in phase transitions. This contribution does not pretend to be an exhaustive review on the subject but aims to introduce some basic concepts in a tutorial way before showing how intricated are these manifestations of anharmonicity. Copyright INTRODUCTIONProperties of materials are dependent on temperature and pressure. All applied research consists in studying the temperature and pressure dependence of their physical properties with a view to preparing the material to exhibit the expected properties in specific conditions of thermal and mechanical stress environment. Basic research consists in relating micro/meso-structural properties with the other physical properties. These relations exist via coupling coefficients which are often defined by a linear relationship. The present review presents the relations which govern the temperature and pressure dependence of the usual spectral parameters such as wavenumber, half-width and intensity of Raman bands. We shall point out the nonlinearity, also defined as anharmonicity, of the corresponding relationships. A tutorial and brief presentation of anharmonic effects in solids can be found in Chapter 8 of Ref. 1. As written by Sherman and Wilkinson, 2,3 in a completely harmonic approximation, where the force constant operating between any two masses is truly a constant and independent of the distance between the masses, the application of pressure would cause no observable frequency shift effects at all. The same statement can be done about the effect of temperature. However, as it becomes evident in the present special issue, this is not verified experimentally.Ł Correspondence to: Guy Lucazeau, LEPMI, (CNRS UMR 5631), Institut National Polytechnique de Grenoble, BP 75, F-38402 St. Martin d'Hères, Cedex, France. E-mail: guy.lucazeau@lepmi.inpg.fr † In memory of Evangelos Anastassakis, who should have been solicited for writing a review paper on such a subject.One of the aims of this paper is to point out that the measurements of temperature-or pressure-induced frequency shifts are measurements of the anharmonicity of the interactions that supply the restoring force constants. Let us point out that because pressure or temperature induces isotropic or anisotropic deformations of molecules and crystals, the pressure or stress-induced and the temperatureinduced frequency shifts  / are mainly determined by the associated deformation V/V. It is thus important to analyze the effects of temperature and pressure together. The origin of the deformation induced by these two external parameters is different. Pressure affects the equilibrium spacings between nuclei, distorts the electron clouds and through them...

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“…7. Even though there is no Raman-active mode in the case of cubic symmetry, 25), 26) we detected a mode around 630 cm -1 , which has been reported to be related to oxygen vacancies in perovskite oxides. 27)-29) Moreover, the broad mode appeared from 350 cm -1 to 400 cm -1 above unit cell free volume values of 2.43 × 10 -2 nm 3 .…”

Section: Jcs-japanmentioning

confidence: 50%

Oxide ion conductivity in (Ba0.3Sr0.2La0.5)(In1-xMx)O2.75 (M = Sc and Yb) systems

Kakinuma¹,

Waki²,

Yamamura³

et al. 2009

J. Ceram. Soc. Japan

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We have investigated the crystal phase and oxide ion conductivity of (Ba0.3Sr0.2La0.5)(In1-xMx)O2.75 (M = Sc and Yb) systems as a function of dopant content and unit cell free volume. All peaks in the XRD diffraction patterns of these systems (x = 0.0 -0.4) were found to be assignable to pure cubic symmetry. The lattice parameter of the Sc-doped system decreased monotonically with rising dopant content, while the Yb-doped one showed a monotonic increase. The oxide ion conductivity of these systems increased with a unit cell free volume. Above a volume of 2.43 × 10 -2 nm 3 , the oxide ion conductivity decreased. The oxygen vacancy content of the systems was controlled to be constant over the whole compositional range, which suggests that the mobile oxygen content should also be constant over the whole range. Above a free volume of 2.43 × 10 -2 nm 3 , a broad Raman mode emerged from 350 cm -1 to 400 cm -1 , which might relate to the local distortion of oxygen octahedra. We conclude that the oxide ion mobility grows with increasing unit cell free volume up to a critical volume, and then the mobility is degraded by the local distortion of the oxygen octahedra.

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A High-Pressure Raman Study of Mixed Perovskites BaCexZr1−xO3 (0≤x≤1)

Cited by 69 publications

References 20 publications

Raman Intensity: An Important Tool in the Study οf Nanomaterials and Nanostructures

Raman Intensity: An Important Tool in the Study οf Nanomaterials and Nanostructures

Effect of pressure and temperature on Raman spectra of solids: anharmonicity

Oxide ion conductivity in (Ba0.3Sr0.2La0.5)(In1-xMx)O2.75 (M = Sc and Yb) systems

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