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| Description
| - Displacive phase transitions in perovskite-like solid solutions AgNb1/2Ta1/2O3 were studied using several diffraction and spectroscopic techniques sensitive to average and local structures. The room-temperature phase of AgNb1/2Ta1/2O3 (M-2) is analogous to that of the end-member AgNbO3 and exhibits Pbcm orthorhombic symmetry with lattice parameters root 2a(c) x root 2a(c) x 4a(c) (a(c) approximate to 4 angstrom refers to an ideal cubic perovskite cell). This structure combines complex octahedral tilting and average antipolar B-cation (Nb, Ta) displacements. Similar to AgNbO3, at higher temperatures, B-cations are disordered among multiple sites displaced along (111), directions. Partial ordering of local B-cation displacements is manifested in the so-called M-3 <-> M-2 transition, which preserves the average Pbcm symmetry determined by the tilted octahedral framework; the transition is accompanied by a broad exploitable maximum of dielectric constant. Ta substitution suppresses this ordering because of the dissimilar off-centering trends for Ta and Nb. According to the extended X-ray absorption fine structure (EXAFS) measurements, Nb cations exhibit much larger local off-center displacements than Ta, consistent with larger dielectric constants typically displayed by niobates compared to tantalates. AgNb1/2Ta1/2O3 maintains residual 8-site disorder down to low temperatures as opposed to 2-site disorder in AgNbO3. Our results suggest that Ag cations also exhibit displacive disorder and, on cooling, undergo ordering coupled to that of the B-cations.
- Displacive phase transitions in perovskite-like solid solutions AgNb1/2Ta1/2O3 were studied using several diffraction and spectroscopic techniques sensitive to average and local structures. The room-temperature phase of AgNb1/2Ta1/2O3 (M-2) is analogous to that of the end-member AgNbO3 and exhibits Pbcm orthorhombic symmetry with lattice parameters root 2a(c) x root 2a(c) x 4a(c) (a(c) approximate to 4 angstrom refers to an ideal cubic perovskite cell). This structure combines complex octahedral tilting and average antipolar B-cation (Nb, Ta) displacements. Similar to AgNbO3, at higher temperatures, B-cations are disordered among multiple sites displaced along (111), directions. Partial ordering of local B-cation displacements is manifested in the so-called M-3 <-> M-2 transition, which preserves the average Pbcm symmetry determined by the tilted octahedral framework; the transition is accompanied by a broad exploitable maximum of dielectric constant. Ta substitution suppresses this ordering because of the dissimilar off-centering trends for Ta and Nb. According to the extended X-ray absorption fine structure (EXAFS) measurements, Nb cations exhibit much larger local off-center displacements than Ta, consistent with larger dielectric constants typically displayed by niobates compared to tantalates. AgNb1/2Ta1/2O3 maintains residual 8-site disorder down to low temperatures as opposed to 2-site disorder in AgNbO3. Our results suggest that Ag cations also exhibit displacive disorder and, on cooling, undergo ordering coupled to that of the B-cations. (en)
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| Title
| - Displacive ordering transitions in perovskite-like AgNb1/2Ta1/2O3./sub
- Displacive ordering transitions in perovskite-like AgNb1/2Ta1/2O3./sub (en)
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| skos:prefLabel
| - Displacive ordering transitions in perovskite-like AgNb1/2Ta1/2O3./sub
- Displacive ordering transitions in perovskite-like AgNb1/2Ta1/2O3./sub (en)
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| skos:notation
| - RIV/68378271:_____/10:00437718!RIV15-AV0-68378271
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| http://linked.open...avai/riv/aktivita
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| http://linked.open...avai/riv/aktivity
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| http://linked.open...iv/cisloPeriodika
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| http://linked.open...vai/riv/dodaniDat
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| http://linked.open...aciTvurceVysledku
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| http://linked.open.../riv/druhVysledku
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| http://linked.open...iv/duvernostUdaju
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| http://linked.open...titaPredkladatele
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| http://linked.open...dnocenehoVysledku
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| http://linked.open...ai/riv/idVysledku
| - RIV/68378271:_____/10:00437718
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| http://linked.open...riv/jazykVysledku
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| http://linked.open.../riv/klicovaSlova
| - phase-transitions; x-ray; dielectric-properties; solid-solutions; scattering; spectra (en)
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| http://linked.open.../riv/klicoveSlovo
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| http://linked.open...odStatuVydavatele
| - US - Spojené státy americké
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| http://linked.open...ontrolniKodProRIV
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| http://linked.open...i/riv/nazevZdroje
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| http://linked.open...in/vavai/riv/obor
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| http://linked.open...ichTvurcuVysledku
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| http://linked.open...cetTvurcuVysledku
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| http://linked.open...UplatneniVysledku
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| http://linked.open...v/svazekPeriodika
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| http://linked.open...iv/tvurceVysledku
| - Pokorný, Jan
- Reaney, I. M.
- Llobet, A.
- Levin, I.
- Krayzman, V.
- Tucker, M. G.
- Woicik, J. C.
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| http://linked.open...ain/vavai/riv/wos
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| http://linked.open...n/vavai/riv/zamer
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| issn
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| number of pages
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| http://bibframe.org/vocab/doi
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