Crystal structure of La(Mg2/3M1/3)O3 (M=Nb,Ta) microwave dielectric ceramics

Jeong Seog Kim; Chae Il Cheon; Hyun Ju Kang; Hae Seop Shim; Chang Hee Lee; Sahn Nam; Jae Dong Byun

doi:10.1016/S0167-577X(98)00177-3

Crystal structure of La(Mg_2/3M_1/3)O₃ (M=Nb,Ta) microwave dielectric ceramics

Jeong Seog Kim^*
, Chae Il Cheon
, Hyun Ju Kang
, Hae Seop Shim
, Chang Hee Lee
, Sahn Nam
, Jae Dong Byun

^*Corresponding author for this work

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

18 Citations (Scopus)

Abstract

Crystal structure of (Ba_1-xLa_x)(Mg_(1+x)/3Nb_(2-x)/3)O ₃ (0.5≤x≤1.0) and La(Mg_2/3Ta_1/3)O₃ microwave dielectric ceramics were analysed by the Rietveld refinement method using X-ray and neutron powder diffraction data. In the composition range 0.5≤x≤0.07, the 1:1 ordered cubic structure (Fm3̄m) is maintained. The end members, La(Mg_2/3Nb_1/3)O₃ and La(Mg_2/3Ta_1/3)O₃, are most successfully refined using an orthorhombic structure Pbnm (a≈5.61, b≈5.64, c≈7.95 Å) contrary to the expectations of earlier works which suggested an 1:1 ordered rhombohedral or monoclinic structure. The structure is similar to CaTiO₃ having oxygen-octahedron tilting and La-displacements. The small ionic size of La⁺³ and hence a small tolerance factor (t≈0.92) is responsible for the orthorhombic distortion. No long-range order of B-site cations exists.

Original language	English
Pages (from-to)	294-299
Number of pages	6
Journal	Materials Letters
Volume	38
Issue number	4
DOIs	https://doi.org/10.1016/S0167-577X(98)00177-3
Publication status	Published - 1999 Feb

Bibliographical note

Funding Information:
This work was supported by Korean Ministry of Education through Research Fund, project No. BSR196-2459.

Keywords

77.84.Dy
77.90.+k
B-site disorder
Crystal structure
La(MgNb)O
Microwave dielectrics
Orthorhombic Pbnm
Rietveld refinement
Space-group
X-ray and neutron diffraction

ASJC Scopus subject areas

General Materials Science
Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering

Access to Document

10.1016/S0167-577X(98)00177-3

Cite this

@article{260c3a826543424ca626f9bd42f10c15,

title = "Crystal structure of La(Mg2/3M1/3)O3 (M=Nb,Ta) microwave dielectric ceramics",

abstract = "Crystal structure of (Ba1-xLax)(Mg(1+x)/3Nb(2-x)/3)O 3 (0.5≤x≤1.0) and La(Mg2/3Ta1/3)O3 microwave dielectric ceramics were analysed by the Rietveld refinement method using X-ray and neutron powder diffraction data. In the composition range 0.5≤x≤0.07, the 1:1 ordered cubic structure (Fm{\=3}m) is maintained. The end members, La(Mg2/3Nb1/3)O3 and La(Mg2/3Ta1/3)O3, are most successfully refined using an orthorhombic structure Pbnm (a≈5.61, b≈5.64, c≈7.95 {\AA}) contrary to the expectations of earlier works which suggested an 1:1 ordered rhombohedral or monoclinic structure. The structure is similar to CaTiO3 having oxygen-octahedron tilting and La-displacements. The small ionic size of La+3 and hence a small tolerance factor (t≈0.92) is responsible for the orthorhombic distortion. No long-range order of B-site cations exists.",

keywords = "77.84.Dy, 77.90.+k, B-site disorder, Crystal structure, La(MgNb)O, Microwave dielectrics, Orthorhombic Pbnm, Rietveld refinement, Space-group, X-ray and neutron diffraction",

author = "Kim, \{Jeong Seog\} and Cheon, \{Chae Il\} and Kang, \{Hyun Ju\} and Shim, \{Hae Seop\} and Lee, \{Chang Hee\} and Sahn Nam and Byun, \{Jae Dong\}",

note = "Funding Information: This work was supported by Korean Ministry of Education through Research Fund, project No. BSR196-2459.",

year = "1999",

month = feb,

doi = "10.1016/S0167-577X(98)00177-3",

language = "English",

volume = "38",

pages = "294--299",

journal = "Materials Letters",

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TY - JOUR

T1 - Crystal structure of La(Mg2/3M1/3)O3 (M=Nb,Ta) microwave dielectric ceramics

AU - Kim, Jeong Seog

AU - Cheon, Chae Il

AU - Kang, Hyun Ju

AU - Shim, Hae Seop

AU - Lee, Chang Hee

AU - Nam, Sahn

AU - Byun, Jae Dong

N1 - Funding Information: This work was supported by Korean Ministry of Education through Research Fund, project No. BSR196-2459.

PY - 1999/2

Y1 - 1999/2

N2 - Crystal structure of (Ba1-xLax)(Mg(1+x)/3Nb(2-x)/3)O 3 (0.5≤x≤1.0) and La(Mg2/3Ta1/3)O3 microwave dielectric ceramics were analysed by the Rietveld refinement method using X-ray and neutron powder diffraction data. In the composition range 0.5≤x≤0.07, the 1:1 ordered cubic structure (Fm3̄m) is maintained. The end members, La(Mg2/3Nb1/3)O3 and La(Mg2/3Ta1/3)O3, are most successfully refined using an orthorhombic structure Pbnm (a≈5.61, b≈5.64, c≈7.95 Å) contrary to the expectations of earlier works which suggested an 1:1 ordered rhombohedral or monoclinic structure. The structure is similar to CaTiO3 having oxygen-octahedron tilting and La-displacements. The small ionic size of La+3 and hence a small tolerance factor (t≈0.92) is responsible for the orthorhombic distortion. No long-range order of B-site cations exists.

AB - Crystal structure of (Ba1-xLax)(Mg(1+x)/3Nb(2-x)/3)O 3 (0.5≤x≤1.0) and La(Mg2/3Ta1/3)O3 microwave dielectric ceramics were analysed by the Rietveld refinement method using X-ray and neutron powder diffraction data. In the composition range 0.5≤x≤0.07, the 1:1 ordered cubic structure (Fm3̄m) is maintained. The end members, La(Mg2/3Nb1/3)O3 and La(Mg2/3Ta1/3)O3, are most successfully refined using an orthorhombic structure Pbnm (a≈5.61, b≈5.64, c≈7.95 Å) contrary to the expectations of earlier works which suggested an 1:1 ordered rhombohedral or monoclinic structure. The structure is similar to CaTiO3 having oxygen-octahedron tilting and La-displacements. The small ionic size of La+3 and hence a small tolerance factor (t≈0.92) is responsible for the orthorhombic distortion. No long-range order of B-site cations exists.

KW - 77.84.Dy

KW - 77.90.+k

KW - B-site disorder

KW - Crystal structure

KW - La(MgNb)O

KW - Microwave dielectrics

KW - Orthorhombic Pbnm

KW - Rietveld refinement

KW - Space-group

KW - X-ray and neutron diffraction

UR - https://www.scopus.com/pages/publications/0033077485

U2 - 10.1016/S0167-577X(98)00177-3

DO - 10.1016/S0167-577X(98)00177-3

M3 - Article

AN - SCOPUS:0033077485

SN - 0167-577X

VL - 38

SP - 294

EP - 299

JO - Materials Letters

JF - Materials Letters

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ER -