Cation ordering transformations in Ba(Mg1/3Ta2/3)O3-BaZrO3 perovskite solid solutions

L. Chai; M. A. Akbas; P. K. Davies; J. B. Parise

doi:10.1016/S0025-5408(97)00104-9

Cation ordering transformations in Ba(Mg_1/3Ta_2/3)O₃-BaZrO₃ perovskite solid solutions

L. Chai
, M. A. Akbas
, P. K. Davies
, J. B. Parise

Geosciences

University of Pennsylvania
Stony Brook University

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

56 Scopus citations

Abstract

The effect of the substitution of BaZrO₃ on the cation ordering in Ba(Mg_1/3Ta_2/3)O₃ was studied using TEM and X-ray and neutron diffraction. Almost no solubility of Zr was found in the 1:2 ordered, trigonal structure of the Ba(Mg_1/3Ta_2/3)O₃ end-member (P 3m1), and a transformation to a 1:1 ordered, cubic (Fm 3m) phase with a = 2a_per occurs for substitution levels between ∼10 and 25 mol% BaZrO₃. The structure of this Ba(β′_1/2β″_1/2)O₃-type phase consists of two distinct octahedral sites, β′ and β″. The occupancies of the two cation positions, refined using the Rietveld method, were found to be consistent with a "random site" model in which β″ is occupied by Ta, and β′ by a random distribution of the remaining cations. The homogeneity range of the 1:1 solid solutions predicted by this model, Ba{[Mg_(2-y)/3Ta_(1-2y)/3 Zr_y]_1/2[Ta]_1/2} O₃ (0.0 < y ≤ 0.5), is in excellent agreement with that observed experimentally.

Original language	English
Pages (from-to)	1261-1269
Number of pages	9
Journal	Materials Research Bulletin
Volume	32
Issue number	9
DOIs	https://doi.org/10.1016/S0025-5408(97)00104-9
State	Published - Sep 1997

Keywords

A. electronic materials
A. oxides
C. X-ray diffraction
D. crystal structure
D. phase equilibria

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10.1016/S0025-5408(97)00104-9

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title = "Cation ordering transformations in Ba(Mg1/3Ta2/3)O3-BaZrO3 perovskite solid solutions",

abstract = "The effect of the substitution of BaZrO3 on the cation ordering in Ba(Mg1/3Ta2/3)O3 was studied using TEM and X-ray and neutron diffraction. Almost no solubility of Zr was found in the 1:2 ordered, trigonal structure of the Ba(Mg1/3Ta2/3)O3 end-member (P 3m1), and a transformation to a 1:1 ordered, cubic (Fm 3m) phase with a = 2aper occurs for substitution levels between ∼10 and 25 mol\% BaZrO3. The structure of this Ba(β′1/2β″1/2)O3-type phase consists of two distinct octahedral sites, β′ and β″. The occupancies of the two cation positions, refined using the Rietveld method, were found to be consistent with a {"}random site{"} model in which β″ is occupied by Ta, and β′ by a random distribution of the remaining cations. The homogeneity range of the 1:1 solid solutions predicted by this model, Ba\{[Mg(2-y)/3Ta(1-2y)/3 Zry]1/2[Ta]1/2\} O3 (0.0 < y ≤ 0.5), is in excellent agreement with that observed experimentally.",

keywords = "A. electronic materials, A. oxides, C. X-ray diffraction, D. crystal structure, D. phase equilibria",

author = "L. Chai and Akbas, \{M. A.\} and Davies, \{P. K.\} and Parise, \{J. B.\}",

year = "1997",

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doi = "10.1016/S0025-5408(97)00104-9",

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T1 - Cation ordering transformations in Ba(Mg1/3Ta2/3)O3-BaZrO3 perovskite solid solutions

AU - Chai, L.

AU - Akbas, M. A.

AU - Davies, P. K.

AU - Parise, J. B.

PY - 1997/9

Y1 - 1997/9

N2 - The effect of the substitution of BaZrO3 on the cation ordering in Ba(Mg1/3Ta2/3)O3 was studied using TEM and X-ray and neutron diffraction. Almost no solubility of Zr was found in the 1:2 ordered, trigonal structure of the Ba(Mg1/3Ta2/3)O3 end-member (P 3m1), and a transformation to a 1:1 ordered, cubic (Fm 3m) phase with a = 2aper occurs for substitution levels between ∼10 and 25 mol% BaZrO3. The structure of this Ba(β′1/2β″1/2)O3-type phase consists of two distinct octahedral sites, β′ and β″. The occupancies of the two cation positions, refined using the Rietveld method, were found to be consistent with a "random site" model in which β″ is occupied by Ta, and β′ by a random distribution of the remaining cations. The homogeneity range of the 1:1 solid solutions predicted by this model, Ba{[Mg(2-y)/3Ta(1-2y)/3 Zry]1/2[Ta]1/2} O3 (0.0 < y ≤ 0.5), is in excellent agreement with that observed experimentally.

AB - The effect of the substitution of BaZrO3 on the cation ordering in Ba(Mg1/3Ta2/3)O3 was studied using TEM and X-ray and neutron diffraction. Almost no solubility of Zr was found in the 1:2 ordered, trigonal structure of the Ba(Mg1/3Ta2/3)O3 end-member (P 3m1), and a transformation to a 1:1 ordered, cubic (Fm 3m) phase with a = 2aper occurs for substitution levels between ∼10 and 25 mol% BaZrO3. The structure of this Ba(β′1/2β″1/2)O3-type phase consists of two distinct octahedral sites, β′ and β″. The occupancies of the two cation positions, refined using the Rietveld method, were found to be consistent with a "random site" model in which β″ is occupied by Ta, and β′ by a random distribution of the remaining cations. The homogeneity range of the 1:1 solid solutions predicted by this model, Ba{[Mg(2-y)/3Ta(1-2y)/3 Zry]1/2[Ta]1/2} O3 (0.0 < y ≤ 0.5), is in excellent agreement with that observed experimentally.

KW - A. electronic materials

KW - A. oxides

KW - C. X-ray diffraction

KW - D. crystal structure

KW - D. phase equilibria

UR - https://www.scopus.com/pages/publications/0031234809

U2 - 10.1016/S0025-5408(97)00104-9

DO - 10.1016/S0025-5408(97)00104-9

M3 - Article

AN - SCOPUS:0031234809

SN - 0025-5408

VL - 32

SP - 1261

EP - 1269

JO - Materials Research Bulletin

JF - Materials Research Bulletin

IS - 9

ER -

Cation ordering transformations in Ba(Mg_1/3Ta_2/3)O₃-BaZrO₃ perovskite solid solutions

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Keywords

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