Local crystal chemistry, structured diffuse scattering and the dielectric properties of (Bi1-xYx)2(MIIINbV)O7 (M=Fe3+, In3+) Bi-pyrochlores

W. Somphon; V. Ting; Y. Liu; R. L. Withers; Q. Zhou; B. J. Kennedy

doi:10.1016/j.jssc.2006.04.046

Local crystal chemistry, structured diffuse scattering and the dielectric properties of (Bi_1-xY_x)₂(M^IIINb^V)O₇ (M=Fe³⁺, In³⁺) Bi-pyrochlores

W. Somphon, V. Ting, Y. Liu, R. L. Withers^*, Q. Zhou, B. J. Kennedy

^*Corresponding author for this work

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

31 Citations (Scopus)

Abstract

Electron diffraction is used to investigate the large amplitude displacive disorder characteristic of the Bi₂(M^IIINb^V)O₇ Bi-pyrochlores, Bi₂InNbO₇ and Bi₂FeNbO₇, as well as of their A site substituted Bi_1.5Y_0.5InNbO₇ and Bi_1.5Y_0.5FeNbO₇ variants. Highly structured diffuse distributions in the form of {110}* sheets of diffuse intensity perpendicular to the six 〈110〉 directions of real space along with 〈111〉* rods of diffuse intensity perpendicular to the four {111} real space planes are observed. The existence of this structured diffuse scattering is interpreted in terms of large amplitude, β-cristobalite-type tetrahedral rotations of the O′A₂ tetrahedral framework sub-structure of the ideal pyrochlore structure type. Bond valence sum calculations are used to understand the local crystal chemistry responsible for such displacive disorder. The frequency-dependent dielectric properties of Bi₂InNbO₇ and Bi₂FeNbO₇ are also investigated along with the effect upon them of A site doping with Y.

Original language	English
Pages (from-to)	2495-2505
Number of pages	11
Journal	Journal of Solid State Chemistry
Volume	179
Issue number	8
DOIs	https://doi.org/10.1016/j.jssc.2006.04.046
Publication status	Published - Aug 2006

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title = "Local crystal chemistry, structured diffuse scattering and the dielectric properties of (Bi1-xYx)2(MIIINbV)O7 (M=Fe3+, In3+) Bi-pyrochlores",

abstract = "Electron diffraction is used to investigate the large amplitude displacive disorder characteristic of the Bi2(MIIINbV)O7 Bi-pyrochlores, Bi2InNbO7 and Bi2FeNbO7, as well as of their A site substituted Bi1.5Y0.5InNbO7 and Bi1.5Y0.5FeNbO7 variants. Highly structured diffuse distributions in the form of {110}* sheets of diffuse intensity perpendicular to the six 〈110〉 directions of real space along with 〈111〉* rods of diffuse intensity perpendicular to the four {111} real space planes are observed. The existence of this structured diffuse scattering is interpreted in terms of large amplitude, β-cristobalite-type tetrahedral rotations of the O′A2 tetrahedral framework sub-structure of the ideal pyrochlore structure type. Bond valence sum calculations are used to understand the local crystal chemistry responsible for such displacive disorder. The frequency-dependent dielectric properties of Bi2InNbO7 and Bi2FeNbO7 are also investigated along with the effect upon them of A site doping with Y.",

keywords = "Bi-pyrochlores, Displacive disorder therein, Electron diffraction investigation of, Structured diffuse scattering",

author = "W. Somphon and V. Ting and Y. Liu and Withers, {R. L.} and Q. Zhou and Kennedy, {B. J.}",

year = "2006",

month = aug,

doi = "10.1016/j.jssc.2006.04.046",

language = "English",

volume = "179",

pages = "2495--2505",

journal = "Journal of Solid State Chemistry",

issn = "0022-4596",

publisher = "Academic Press Inc.",

number = "8",

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T1 - Local crystal chemistry, structured diffuse scattering and the dielectric properties of (Bi1-xYx)2(MIIINbV)O7 (M=Fe3+, In3+) Bi-pyrochlores

AU - Somphon, W.

AU - Ting, V.

AU - Liu, Y.

AU - Withers, R. L.

AU - Zhou, Q.

AU - Kennedy, B. J.

PY - 2006/8

Y1 - 2006/8

N2 - Electron diffraction is used to investigate the large amplitude displacive disorder characteristic of the Bi2(MIIINbV)O7 Bi-pyrochlores, Bi2InNbO7 and Bi2FeNbO7, as well as of their A site substituted Bi1.5Y0.5InNbO7 and Bi1.5Y0.5FeNbO7 variants. Highly structured diffuse distributions in the form of {110}* sheets of diffuse intensity perpendicular to the six 〈110〉 directions of real space along with 〈111〉* rods of diffuse intensity perpendicular to the four {111} real space planes are observed. The existence of this structured diffuse scattering is interpreted in terms of large amplitude, β-cristobalite-type tetrahedral rotations of the O′A2 tetrahedral framework sub-structure of the ideal pyrochlore structure type. Bond valence sum calculations are used to understand the local crystal chemistry responsible for such displacive disorder. The frequency-dependent dielectric properties of Bi2InNbO7 and Bi2FeNbO7 are also investigated along with the effect upon them of A site doping with Y.

AB - Electron diffraction is used to investigate the large amplitude displacive disorder characteristic of the Bi2(MIIINbV)O7 Bi-pyrochlores, Bi2InNbO7 and Bi2FeNbO7, as well as of their A site substituted Bi1.5Y0.5InNbO7 and Bi1.5Y0.5FeNbO7 variants. Highly structured diffuse distributions in the form of {110}* sheets of diffuse intensity perpendicular to the six 〈110〉 directions of real space along with 〈111〉* rods of diffuse intensity perpendicular to the four {111} real space planes are observed. The existence of this structured diffuse scattering is interpreted in terms of large amplitude, β-cristobalite-type tetrahedral rotations of the O′A2 tetrahedral framework sub-structure of the ideal pyrochlore structure type. Bond valence sum calculations are used to understand the local crystal chemistry responsible for such displacive disorder. The frequency-dependent dielectric properties of Bi2InNbO7 and Bi2FeNbO7 are also investigated along with the effect upon them of A site doping with Y.

KW - Bi-pyrochlores

KW - Displacive disorder therein

KW - Electron diffraction investigation of

KW - Structured diffuse scattering

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DO - 10.1016/j.jssc.2006.04.046

M3 - Article

SN - 0022-4596

VL - 179

SP - 2495

EP - 2505

JO - Journal of Solid State Chemistry

JF - Journal of Solid State Chemistry

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ER -

Local crystal chemistry, structured diffuse scattering and the dielectric properties of (Bi_1-xY_x)₂(M^IIINb^V)O₇ (M=Fe³⁺, In³⁺) Bi-pyrochlores

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