Modulated Structure of Misfit-Layered Cobalt Oxide [Ca2(Co 0.65Cu0.35)2O4] 0.63CoO2

Yuzuru Miyazaki; Tatsuro Miura; Mitsuko Onoda; Masaya Uchida; Yoshinobu Ishii; Yasuhiro Ono; Yukio Morii; Tsuyoshi Kajitani

doi:10.1143/jjap.42.7467

Modulated Structure of Misfit-Layered Cobalt Oxide [Ca₂(Co _0.65Cu_0.35)₂O₄] _0.63CoO₂

Yuzuru Miyazaki, Tatsuro Miura, Mitsuko Onoda, Masaya Uchida, Yoshinobu Ishii, Yasuhiro Ono, Yukio Morii, Tsuyoshi Kajitani

ENG - Applied Physics

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

26 Citations (Scopus)

Abstract

We have determined the crystal structure of novel thermoelectric compound [Ca₂(Co_0.65Cu_0.35)₂O ₄]_0.63CoO₂ by a superspace group approach. Structural parameters have been refined with a superspace group of C2/m(1 p 0) s0 using powder neutron diffraction data collected at 293 K. The compound consists of mutually interpenetrating triangular CoO₂ layers and distorted four-layered rock salt-type Ca₂(Co_0.65Cu _0.35)₂O₄ slabs, which are incommensurate parallel to the b-axis. The CoO₂ layer is composed of the CdI ₂-type edge-shared CoO₆ octahedra. Both the subsystems have common a- and c-axes, and β-angle with a = 4.8212(4) Å, c = 12.7671(8) Å and β= 93.93(1)°. The e-axis lengths are b ₁ = 2.8103(3) Å for the [CoO₂] subsystem and b ₂ = 4.4915(3) Å for the [Ca₂(Co _0.65Cu_0.35)₂O₄] subsystem. A marked displacive modulation of the (Co,Cu) and O sites in the [Ca₂(Co _0.65Cu_0.35)₂O₄] subsystem has been observed, yielding a large fluctuation of the (Co,Cu)-O distances in the range from 1.8 Å to 2.7 Å. Cu²⁺ ions appear to play an important role in stabilizing such a four-atom thick subsystem in this compound.

Original language	English
Pages (from-to)	7467-7473
Number of pages	7
Journal	Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume	42
Issue number	12
DOIs	https://doi.org/10.1143/jjap.42.7467
Publication status	Published - 2003 Dec

Keywords

Calcium cobalt copper oxide
Misfit-layered structure
Rietveld refinement
Superspace group
Thermoelectric compound

ASJC Scopus subject areas

Engineering(all)
Physics and Astronomy(all)

Access to Document

10.1143/jjap.42.7467

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Modulated Structure of Misfit-Layered Cobalt Oxide [Ca₂(Co _0.65Cu_0.35)₂O₄] _0.63CoO₂. / Miyazaki, Yuzuru; Miura, Tatsuro; Onoda, Mitsuko; Uchida, Masaya; Ishii, Yoshinobu; Ono, Yasuhiro; Morii, Yukio; Kajitani, Tsuyoshi.

In: Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers, Vol. 42, No. 12, 12.2003, p. 7467-7473.

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

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title = "Modulated Structure of Misfit-Layered Cobalt Oxide [Ca2(Co 0.65Cu0.35)2O4] 0.63CoO2",

abstract = "We have determined the crystal structure of novel thermoelectric compound [Ca2(Co0.65Cu0.35)2O 4]0.63CoO2 by a superspace group approach. Structural parameters have been refined with a superspace group of C2/m(1 p 0) s0 using powder neutron diffraction data collected at 293 K. The compound consists of mutually interpenetrating triangular CoO2 layers and distorted four-layered rock salt-type Ca2(Co0.65Cu 0.35)2O4 slabs, which are incommensurate parallel to the b-axis. The CoO2 layer is composed of the CdI 2-type edge-shared CoO6 octahedra. Both the subsystems have common a- and c-axes, and β-angle with a = 4.8212(4) {\AA}, c = 12.7671(8) {\AA} and β= 93.93(1)°. The e-axis lengths are b 1 = 2.8103(3) {\AA} for the [CoO2] subsystem and b 2 = 4.4915(3) {\AA} for the [Ca2(Co 0.65Cu0.35)2O4] subsystem. A marked displacive modulation of the (Co,Cu) and O sites in the [Ca2(Co 0.65Cu0.35)2O4] subsystem has been observed, yielding a large fluctuation of the (Co,Cu)-O distances in the range from 1.8 {\AA} to 2.7 {\AA}. Cu2+ ions appear to play an important role in stabilizing such a four-atom thick subsystem in this compound.",

keywords = "Calcium cobalt copper oxide, Misfit-layered structure, Rietveld refinement, Superspace group, Thermoelectric compound",

author = "Yuzuru Miyazaki and Tatsuro Miura and Mitsuko Onoda and Masaya Uchida and Yoshinobu Ishii and Yasuhiro Ono and Yukio Morii and Tsuyoshi Kajitani",

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T1 - Modulated Structure of Misfit-Layered Cobalt Oxide [Ca2(Co 0.65Cu0.35)2O4] 0.63CoO2

AU - Miyazaki, Yuzuru

AU - Miura, Tatsuro

AU - Onoda, Mitsuko

AU - Uchida, Masaya

AU - Ishii, Yoshinobu

AU - Ono, Yasuhiro

AU - Morii, Yukio

AU - Kajitani, Tsuyoshi

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N2 - We have determined the crystal structure of novel thermoelectric compound [Ca2(Co0.65Cu0.35)2O 4]0.63CoO2 by a superspace group approach. Structural parameters have been refined with a superspace group of C2/m(1 p 0) s0 using powder neutron diffraction data collected at 293 K. The compound consists of mutually interpenetrating triangular CoO2 layers and distorted four-layered rock salt-type Ca2(Co0.65Cu 0.35)2O4 slabs, which are incommensurate parallel to the b-axis. The CoO2 layer is composed of the CdI 2-type edge-shared CoO6 octahedra. Both the subsystems have common a- and c-axes, and β-angle with a = 4.8212(4) Å, c = 12.7671(8) Å and β= 93.93(1)°. The e-axis lengths are b 1 = 2.8103(3) Å for the [CoO2] subsystem and b 2 = 4.4915(3) Å for the [Ca2(Co 0.65Cu0.35)2O4] subsystem. A marked displacive modulation of the (Co,Cu) and O sites in the [Ca2(Co 0.65Cu0.35)2O4] subsystem has been observed, yielding a large fluctuation of the (Co,Cu)-O distances in the range from 1.8 Å to 2.7 Å. Cu2+ ions appear to play an important role in stabilizing such a four-atom thick subsystem in this compound.

AB - We have determined the crystal structure of novel thermoelectric compound [Ca2(Co0.65Cu0.35)2O 4]0.63CoO2 by a superspace group approach. Structural parameters have been refined with a superspace group of C2/m(1 p 0) s0 using powder neutron diffraction data collected at 293 K. The compound consists of mutually interpenetrating triangular CoO2 layers and distorted four-layered rock salt-type Ca2(Co0.65Cu 0.35)2O4 slabs, which are incommensurate parallel to the b-axis. The CoO2 layer is composed of the CdI 2-type edge-shared CoO6 octahedra. Both the subsystems have common a- and c-axes, and β-angle with a = 4.8212(4) Å, c = 12.7671(8) Å and β= 93.93(1)°. The e-axis lengths are b 1 = 2.8103(3) Å for the [CoO2] subsystem and b 2 = 4.4915(3) Å for the [Ca2(Co 0.65Cu0.35)2O4] subsystem. A marked displacive modulation of the (Co,Cu) and O sites in the [Ca2(Co 0.65Cu0.35)2O4] subsystem has been observed, yielding a large fluctuation of the (Co,Cu)-O distances in the range from 1.8 Å to 2.7 Å. Cu2+ ions appear to play an important role in stabilizing such a four-atom thick subsystem in this compound.

KW - Calcium cobalt copper oxide

KW - Misfit-layered structure

KW - Rietveld refinement

KW - Superspace group

KW - Thermoelectric compound

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