Extended X-ray absorption fine structure analysis of (Ca,Nd)(Ti,Al)O3 perovskite ceramics used in cellular base stations

Eric Rop Kipkoech; Feridoon Azough; Robert Freer; Julian FrederickWillem Mosselmans

doi:10.1016/j.actamat.2005.11.002

Extended X-ray absorption fine structure analysis of (Ca,Nd)(Ti,Al)O3 perovskite ceramics used in cellular base stations

Eric Rop Kipkoech, Feridoon Azough, Robert Freer, Julian FrederickWillem Mosselmans

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

Abstract

The local structural environments for Ca, Nd and Ti atoms in Ca0.7Nd0.3Ti0.7Al0.3O3 ceramics were studied at 298 K using extended X-ray absorption fine structure (EXAFS) analysis. The theoretical EXAFS spectra were in excellent agreement with experimental EXAFS data. There was very good agreement between EXAFS-derived distances and X-ray data for Ti (all three shells), but for Ca and Nd the EXAFS distances for the first co-ordination shell (Ca-O and Nd-O) were significantly less than values obtained from X-ray analysis and Shannon's ionic radii; also, co-ordination numbers were inconsistent with X-ray results for Ca and Nd. The similarity in the data for Ca and Nd confirms that the cations sit in a shared site, where there is large disorder in (Ca/Nd)-O distances. Bond valence sums for the Ti site were abnormally high, indicating compression of the site, possibly as a result of compositionally induced strain. © 2005.

Original language	English
Pages (from-to)	2305-2309
Number of pages	4
Journal	Acta Materialia
Volume	54
Issue number	9
DOIs	https://doi.org/10.1016/j.actamat.2005.11.002
Publication status	Published - May 2006

Keywords

Ceramics
Dielectrics
EXAFS
Perovskites

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@article{0537f82abb9e400fa26d81e130d66195,

title = "Extended X-ray absorption fine structure analysis of (Ca,Nd)(Ti,Al)O3 perovskite ceramics used in cellular base stations",

abstract = "The local structural environments for Ca, Nd and Ti atoms in Ca0.7Nd0.3Ti0.7Al0.3O3 ceramics were studied at 298 K using extended X-ray absorption fine structure (EXAFS) analysis. The theoretical EXAFS spectra were in excellent agreement with experimental EXAFS data. There was very good agreement between EXAFS-derived distances and X-ray data for Ti (all three shells), but for Ca and Nd the EXAFS distances for the first co-ordination shell (Ca-O and Nd-O) were significantly less than values obtained from X-ray analysis and Shannon's ionic radii; also, co-ordination numbers were inconsistent with X-ray results for Ca and Nd. The similarity in the data for Ca and Nd confirms that the cations sit in a shared site, where there is large disorder in (Ca/Nd)-O distances. Bond valence sums for the Ti site were abnormally high, indicating compression of the site, possibly as a result of compositionally induced strain. {\textcopyright} 2005.",

keywords = "Ceramics, Dielectrics, EXAFS, Perovskites",

author = "Kipkoech, {Eric Rop} and Feridoon Azough and Robert Freer and Mosselmans, {Julian FrederickWillem}",

year = "2006",

month = may,

doi = "10.1016/j.actamat.2005.11.002",

language = "English",

volume = "54",

pages = "2305--2309",

journal = "Acta Materialia",

issn = "1873-2453",

publisher = "Elsevier BV",

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TY - JOUR

T1 - Extended X-ray absorption fine structure analysis of (Ca,Nd)(Ti,Al)O3 perovskite ceramics used in cellular base stations

AU - Kipkoech, Eric Rop

AU - Azough, Feridoon

AU - Freer, Robert

AU - Mosselmans, Julian FrederickWillem

PY - 2006/5

Y1 - 2006/5

N2 - The local structural environments for Ca, Nd and Ti atoms in Ca0.7Nd0.3Ti0.7Al0.3O3 ceramics were studied at 298 K using extended X-ray absorption fine structure (EXAFS) analysis. The theoretical EXAFS spectra were in excellent agreement with experimental EXAFS data. There was very good agreement between EXAFS-derived distances and X-ray data for Ti (all three shells), but for Ca and Nd the EXAFS distances for the first co-ordination shell (Ca-O and Nd-O) were significantly less than values obtained from X-ray analysis and Shannon's ionic radii; also, co-ordination numbers were inconsistent with X-ray results for Ca and Nd. The similarity in the data for Ca and Nd confirms that the cations sit in a shared site, where there is large disorder in (Ca/Nd)-O distances. Bond valence sums for the Ti site were abnormally high, indicating compression of the site, possibly as a result of compositionally induced strain. © 2005.

AB - The local structural environments for Ca, Nd and Ti atoms in Ca0.7Nd0.3Ti0.7Al0.3O3 ceramics were studied at 298 K using extended X-ray absorption fine structure (EXAFS) analysis. The theoretical EXAFS spectra were in excellent agreement with experimental EXAFS data. There was very good agreement between EXAFS-derived distances and X-ray data for Ti (all three shells), but for Ca and Nd the EXAFS distances for the first co-ordination shell (Ca-O and Nd-O) were significantly less than values obtained from X-ray analysis and Shannon's ionic radii; also, co-ordination numbers were inconsistent with X-ray results for Ca and Nd. The similarity in the data for Ca and Nd confirms that the cations sit in a shared site, where there is large disorder in (Ca/Nd)-O distances. Bond valence sums for the Ti site were abnormally high, indicating compression of the site, possibly as a result of compositionally induced strain. © 2005.

KW - Ceramics

KW - Dielectrics

KW - EXAFS

KW - Perovskites

U2 - 10.1016/j.actamat.2005.11.002

DO - 10.1016/j.actamat.2005.11.002

M3 - Article

SN - 1873-2453

VL - 54

SP - 2305

EP - 2309

JO - Acta Materialia

JF - Acta Materialia

IS - 9

ER -

Extended X-ray absorption fine structure analysis of (Ca,Nd)(Ti,Al)O3 perovskite ceramics used in cellular base stations

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Keywords

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