Synchrotron radiation topography studies of the phase transition in LaGaO3 crystals

Yao, G.-D.; Dudley, Michael; Wang, Yanbin; Liu, X.; Liebermann, Robert C.

doi:10.1016/0168-583x(91)96058-s

Cited by 4 publications

(1 citation statement)

References 5 publications

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“…Due to symmetry lowering, twins are very frequently observed in perovskites and were described by many authors in the case of LaGaO 3 (Wang et al ., 1991; Yao et al ., 1991; Fink‐Finowicki et al ., 1992; Bdikin et al ., 1993; Wang & Lu, 2006; Wang & Lu, 2007).…”

Section: Identification Of a Twinmentioning

confidence: 99%

Contribution of electron precession to the study of perovskites displaying small symmetry departures from the ideal cubic ABO₃ perovskite: applications to the LaGaO₃ and LSGM perovskites

Morniroli

Auchterlonie

Drennan

et al. 2008

Journal of Microscopy

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SummaryElectron microscopy and electron diffraction are well adapted to the study of the fine-grained, faulted pure and doped LaGaO 3 and LSGM perovskites in which the latter is useful for fuel cell components. Because these perovskites display small symmetry departures from an ideal cubic ABO 3 perovskite, many conventional electron diffraction patterns look similar and cannot be indexed without ambiguity. Electron precession can easily overcome this difficulty mainly because the intensity of the diffracted beams on the precession patterns is integrated over a large deviation domain around the exact Bragg condition. This integrated intensity can be trusted and taken into account to identify the 'ideal' symmetry of the precession patterns (the symmetry which takes into account both the position and the intensity of the diffracted beams). In the present case of the LaGaO 3 and LSGM perovskites, the determination of the 'ideal' symmetry of the precession patterns is based on the observation of weak 'superlattice' reflections typical of the symmetry departures. It allows an easy and sure identification of any zone axes as well as the correct attribution of hkl indices to each of the diffracted beams. Examples of applications of this analysis to the characterizations of twins and to the identification of the space groups are given. This contribution of electron precession can be easily extended to any other perovskites or to any crystals displaying small symmetry departures.

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Section: Identification Of a Twinmentioning

confidence: 99%

Contribution of electron precession to the study of perovskites displaying small symmetry departures from the ideal cubic ABO₃ perovskite: applications to the LaGaO₃ and LSGM perovskites

Morniroli

Auchterlonie

Drennan

et al. 2008

Journal of Microscopy

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Phase constitution in Sr and Mg doped LaGaO3 system

Zheng

Bordia

Pederson

2004

Materials Research Bulletin

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Synchrotron topography of phase transitions in perovskite-like crystals

Dudley

Yao

1993

J. Phys. D: Appl. Phys.

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In situ observations have been made of the first-order phase transition occurring at approximately 145 degrees C in a large LaGaO3 single crystal, and the second-order phase transition occurring at approximately 435 degrees C in a large LaAlO3 single crystal, using synchrotron white beam X-ray diffraction topography. In the case of LaGaO3, the high-temperature rhombohedral phase reflections gradually replace the low-temperature orthorhombic reflections as the transition temperature is approached. In the case of LaAlO3, the magnitude of this image shift continuously decreased in magnitude as the temperature approaches the transition point, which along with the gradual distortion of the diffraction pattern, confirms the second-order nature of this transition. As the transition is surpassed, twinning completely disappears in the crystal, as expected, since the twin planes in the rhombohedral phase become mirror planes in the cubic phase.

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Synchrotron radiation topography studies of the phase transition in LaGaO3 crystals

Cited by 4 publications

References 5 publications

Contribution of electron precession to the study of perovskites displaying small symmetry departures from the ideal cubic ABO₃ perovskite: applications to the LaGaO₃ and LSGM perovskites

Contribution of electron precession to the study of perovskites displaying small symmetry departures from the ideal cubic ABO₃ perovskite: applications to the LaGaO₃ and LSGM perovskites

Phase constitution in Sr and Mg doped LaGaO3 system

Synchrotron topography of phase transitions in perovskite-like crystals

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Synchrotron radiation topography studies of the phase transition in LaGaO3 crystals

Cited by 4 publications

References 5 publications

Contribution of electron precession to the study of perovskites displaying small symmetry departures from the ideal cubic ABO3 perovskite: applications to the LaGaO3 and LSGM perovskites

Contribution of electron precession to the study of perovskites displaying small symmetry departures from the ideal cubic ABO3 perovskite: applications to the LaGaO3 and LSGM perovskites

Phase constitution in Sr and Mg doped LaGaO3 system

Synchrotron topography of phase transitions in perovskite-like crystals

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Product

Resources

About

Contribution of electron precession to the study of perovskites displaying small symmetry departures from the ideal cubic ABO₃ perovskite: applications to the LaGaO₃ and LSGM perovskites

Contribution of electron precession to the study of perovskites displaying small symmetry departures from the ideal cubic ABO₃ perovskite: applications to the LaGaO₃ and LSGM perovskites