The local crystal chemistry and dielectric properties of the cubic pyrochlore phase in the Bi2O3{single bond}M2+O{single bond}Nb2O5 (M2+=Ni2+ and Mg2+) systems

Binh Nguyen; Yun Liu; Ray L. Withers

doi:10.1016/j.jssc.2006.10.039

The local crystal chemistry and dielectric properties of the cubic pyrochlore phase in the Bi₂O₃{single bond}M²⁺O{single bond}Nb₂O₅ (M²⁺=Ni²⁺ and Mg²⁺) systems

Binh Nguyen, Yun Liu, Ray L. Withers^*

^*Corresponding author for this work

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

57 Citations (Scopus)

Abstract

The composition, dielectric properties and inherent displacive disorder of a Bi-based, misplaced-displacive cubic pyrochlore phase found in two ternary Bi₂O₃{single bond}M²⁺O{single bond}Nb₂O₅ (M=Ni and Mg) systems has been investigated. The dielectric permittivities (up to 1 MHz) of (Bi_0.825Ni_0.125□_0.05)₂(Ni_0.25Nb_0.75)₂O₇ and (Bi_0.835Mg_0.085□_0.08)₂(Mg_0.235Nb_0.765)₂O₇ at room temperature are found to be 116 and 151, respectively, while the dielectric loss tangents are 0.00065 and 0.00042, respectively, at 100 kHz. A highly structured characteristic diffuse intensity distribution apparent in electron diffraction is reported in both cases and partially 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 investigate the local crystal chemistry responsible for this displacive disorder.

Original language	English
Pages (from-to)	549-557
Number of pages	9
Journal	Journal of Solid State Chemistry
Volume	180
Issue number	2
DOIs	https://doi.org/10.1016/j.jssc.2006.10.039
Publication status	Published - Feb 2007

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title = "The local crystal chemistry and dielectric properties of the cubic pyrochlore phase in the Bi2O3\{single bond\}M2+O\{single bond\}Nb2O5 (M2+=Ni2+ and Mg2+) systems",

abstract = "The composition, dielectric properties and inherent displacive disorder of a Bi-based, misplaced-displacive cubic pyrochlore phase found in two ternary Bi2O3\{single bond\}M2+O\{single bond\}Nb2O5 (M=Ni and Mg) systems has been investigated. The dielectric permittivities (up to 1 MHz) of (Bi0.825Ni0.125□0.05)2(Ni0.25Nb0.75)2O7 and (Bi0.835Mg0.085□0.08)2(Mg0.235Nb0.765)2O7 at room temperature are found to be 116 and 151, respectively, while the dielectric loss tangents are 0.00065 and 0.00042, respectively, at 100 kHz. A highly structured characteristic diffuse intensity distribution apparent in electron diffraction is reported in both cases and partially 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 investigate the local crystal chemistry responsible for this displacive disorder.",

keywords = "Misplaced-displacive cubic pyrochlores",

author = "Binh Nguyen and Yun Liu and Withers, \{Ray L.\}",

year = "2007",

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doi = "10.1016/j.jssc.2006.10.039",

language = "English",

volume = "180",

pages = "549--557",

journal = "Journal of Solid State Chemistry",

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T1 - The local crystal chemistry and dielectric properties of the cubic pyrochlore phase in the Bi2O3{single bond}M2+O{single bond}Nb2O5 (M2+=Ni2+ and Mg2+) systems

AU - Nguyen, Binh

AU - Liu, Yun

AU - Withers, Ray L.

PY - 2007/2

Y1 - 2007/2

N2 - The composition, dielectric properties and inherent displacive disorder of a Bi-based, misplaced-displacive cubic pyrochlore phase found in two ternary Bi2O3{single bond}M2+O{single bond}Nb2O5 (M=Ni and Mg) systems has been investigated. The dielectric permittivities (up to 1 MHz) of (Bi0.825Ni0.125□0.05)2(Ni0.25Nb0.75)2O7 and (Bi0.835Mg0.085□0.08)2(Mg0.235Nb0.765)2O7 at room temperature are found to be 116 and 151, respectively, while the dielectric loss tangents are 0.00065 and 0.00042, respectively, at 100 kHz. A highly structured characteristic diffuse intensity distribution apparent in electron diffraction is reported in both cases and partially 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 investigate the local crystal chemistry responsible for this displacive disorder.

AB - The composition, dielectric properties and inherent displacive disorder of a Bi-based, misplaced-displacive cubic pyrochlore phase found in two ternary Bi2O3{single bond}M2+O{single bond}Nb2O5 (M=Ni and Mg) systems has been investigated. The dielectric permittivities (up to 1 MHz) of (Bi0.825Ni0.125□0.05)2(Ni0.25Nb0.75)2O7 and (Bi0.835Mg0.085□0.08)2(Mg0.235Nb0.765)2O7 at room temperature are found to be 116 and 151, respectively, while the dielectric loss tangents are 0.00065 and 0.00042, respectively, at 100 kHz. A highly structured characteristic diffuse intensity distribution apparent in electron diffraction is reported in both cases and partially 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 investigate the local crystal chemistry responsible for this displacive disorder.

KW - Misplaced-displacive cubic pyrochlores

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U2 - 10.1016/j.jssc.2006.10.039

DO - 10.1016/j.jssc.2006.10.039

M3 - Article

SN - 0022-4596

VL - 180

SP - 549

EP - 557

JO - Journal of Solid State Chemistry

JF - Journal of Solid State Chemistry

IS - 2

ER -

The local crystal chemistry and dielectric properties of the cubic pyrochlore phase in the Bi₂O₃{single bond}M²⁺O{single bond}Nb₂O₅ (M²⁺=Ni²⁺ and Mg²⁺) systems

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