Divacancy superstructures in thermoelectric calcium-doped sodium cobaltate

Dan Porter; M. Roger; M. J. Gutmann; Uthay Sivaperumal; D. Prabhakaran; A. T. Boothroyd; Manoj Pandiyan; Jon Goff

doi:10.1103/PhysRevB.90.054101

Divacancy superstructures in thermoelectric calcium-doped sodium cobaltate

Dan Porter, M. Roger, M. J. Gutmann, Uthay Sivaperumal, D. Prabhakaran, A. T. Boothroyd, Manoj Pandiyan, Jon Goff

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Abstract

We have grown single crystals of Na_xCa_yCoO₂ and determined their superstructures as a function of composition using neutron and x-ray diffraction. Inclusion of Ca²⁺ stabilizes a single superstructure across a wide range of temperatures and concentrations. The superstructure in the Na⁺ layers is based on arrays of divacancy clusters with Ca²⁺ ions occupying the central site, and it has an ideal concentration Na_4/7Ca_1/7CoO₂. Previous measurements of the thermoelectric properties on this system are discussed in light of this superstructure. Na_4/7Ca_1/7CoO₂ corresponds to the maximum in thermoelectric performance of this system.

Original language	English
Article number	054101
Journal	Physical Review B
Volume	90
DOIs	https://doi.org/10.1103/PhysRevB.90.054101
Publication status	Published - 4 Aug 2014

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10.1103/PhysRevB.90.054101

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http://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.054101

Synthesis and structure of new thermoelectric oxide crystals
Goff, J. (PI)
International Scientific Interchange Scheme
1/10/09 → 30/09/13
Project: Research

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title = "Divacancy superstructures in thermoelectric calcium-doped sodium cobaltate",

abstract = "We have grown single crystals of NaxCayCoO2 and determined their superstructures as a function of composition using neutron and x-ray diffraction. Inclusion of Ca2+ stabilizes a single superstructure across a wide range of temperatures and concentrations. The superstructure in the Na+ layers is based on arrays of divacancy clusters with Ca2+ ions occupying the central site, and it has an ideal concentration Na4/7Ca1/7CoO2. Previous measurements of the thermoelectric properties on this system are discussed in light of this superstructure. Na4/7Ca1/7CoO2 corresponds to the maximum in thermoelectric performance of this system.",

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AU - Porter, Dan

AU - Roger, M.

AU - Gutmann, M. J.

AU - Sivaperumal, Uthay

AU - Prabhakaran, D.

AU - Boothroyd, A. T.

AU - Pandiyan, Manoj

AU - Goff, Jon

PY - 2014/8/4

Y1 - 2014/8/4

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AB - We have grown single crystals of NaxCayCoO2 and determined their superstructures as a function of composition using neutron and x-ray diffraction. Inclusion of Ca2+ stabilizes a single superstructure across a wide range of temperatures and concentrations. The superstructure in the Na+ layers is based on arrays of divacancy clusters with Ca2+ ions occupying the central site, and it has an ideal concentration Na4/7Ca1/7CoO2. Previous measurements of the thermoelectric properties on this system are discussed in light of this superstructure. Na4/7Ca1/7CoO2 corresponds to the maximum in thermoelectric performance of this system.

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DO - 10.1103/PhysRevB.90.054101

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SN - 1098-0121

VL - 90

JO - Physical Review B

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M1 - 054101

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Divacancy superstructures in thermoelectric calcium-doped sodium cobaltate

Abstract

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Projects

Synthesis and structure of new thermoelectric oxide crystals

Cite this