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

Department of Materials Science and Engineering

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

5 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

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

Materials Science(all)
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",

issn = "0167-577X",

publisher = "Elsevier",

number = "4",

}

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

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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

IS - 4

ER -