An X-ray study of coupling between acoustic and optic modes at the ferroelastic phase transition in As2O5

W. W. Schmahl; S. A.T. Redfern

doi:10.1088/0022-3719/21/20/007

An X-ray study of coupling between acoustic and optic modes at the ferroelastic phase transition in As₂O₅

W. W. Schmahl, S. A.T. Redfern

University of Cambridge

Research output: Contribution to journal › Article › peer-review

7 Citations (Scopus)

Abstract

The intensity of the 006 reflection of As₂O₅ has been measured as a function of temperature by single-crystal X-ray diffraction across the proper ferroelastic phase transition at T_c=578 K. The intensity is proportional to mod T_c-T mod in the low-temperature (P2₁2₁2₁) phase corresponding to second-order Landau behaviour, and vanishes above T_c confirming the previously postulated high-temperature symmetry P4₁2₁2. The structure factor of the 006 reflection has been expressed in terms of the amplitude of a cooperative atomic displacement pattern arising from coupling between the critical acoustic instability and optic phonons.

Original language	English
Pages (from-to)	3719-3725
Number of pages	7
Journal	Journal of Physics C: Solid State Physics
Volume	21
Issue number	20
DOIs	https://doi.org/10.1088/0022-3719/21/20/007
Publication status	Published - Jul 20 1988
Externally published	Yes

ASJC Scopus Subject Areas

Condensed Matter Physics
General Engineering
General Physics and Astronomy

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10.1088/0022-3719/21/20/007

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abstract = "The intensity of the 006 reflection of As2O5 has been measured as a function of temperature by single-crystal X-ray diffraction across the proper ferroelastic phase transition at Tc=578 K. The intensity is proportional to mod Tc-T mod in the low-temperature (P212121) phase corresponding to second-order Landau behaviour, and vanishes above Tc confirming the previously postulated high-temperature symmetry P41212. The structure factor of the 006 reflection has been expressed in terms of the amplitude of a cooperative atomic displacement pattern arising from coupling between the critical acoustic instability and optic phonons.",

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Y1 - 1988/7/20

N2 - The intensity of the 006 reflection of As2O5 has been measured as a function of temperature by single-crystal X-ray diffraction across the proper ferroelastic phase transition at Tc=578 K. The intensity is proportional to mod Tc-T mod in the low-temperature (P212121) phase corresponding to second-order Landau behaviour, and vanishes above Tc confirming the previously postulated high-temperature symmetry P41212. The structure factor of the 006 reflection has been expressed in terms of the amplitude of a cooperative atomic displacement pattern arising from coupling between the critical acoustic instability and optic phonons.

AB - The intensity of the 006 reflection of As2O5 has been measured as a function of temperature by single-crystal X-ray diffraction across the proper ferroelastic phase transition at Tc=578 K. The intensity is proportional to mod Tc-T mod in the low-temperature (P212121) phase corresponding to second-order Landau behaviour, and vanishes above Tc confirming the previously postulated high-temperature symmetry P41212. The structure factor of the 006 reflection has been expressed in terms of the amplitude of a cooperative atomic displacement pattern arising from coupling between the critical acoustic instability and optic phonons.

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JF - Journal of Physics C: Solid State Physics

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An X-ray study of coupling between acoustic and optic modes at the ferroelastic phase transition in As₂O₅

Abstract

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