Tuning Co Valence State in Cobalt Oxyhydrate Superconductor by Postreduction

We report a successful tuning of Co valence state in cobalt oxyhydrate superconductor via a facile postreduction using NaOH as reducing agent. The change in Co valence was precisely determined by measuring the volume of the released oxygen. The possible hydronium incorporation was greatly suppressed...

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Bibliographic Details
Published inChemistry of materials Vol. 19; no. 18; pp. 4432 - 4435
Main Authors Ren, Zhi, Luo, Jian-lin, Xu, Zhu-an, Cao, Guang-han
Format Journal Article
LanguageEnglish
Published American Chemical Society 04.09.2007
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Summary:We report a successful tuning of Co valence state in cobalt oxyhydrate superconductor via a facile postreduction using NaOH as reducing agent. The change in Co valence was precisely determined by measuring the volume of the released oxygen. The possible hydronium incorporation was greatly suppressed in concentrated NaOH solution, making the absolute Co valence determinable. As a result, an updated superconducting phase diagram was obtained, which shows that the superconducting transition temperature increases monotonically with increasing Co valence in a narrow range from +3.58 to +3.65.
Bibliography:istex:AC6F8F9171ECDB09BE8CBC278A2B8A49E2C6A60E
ark:/67375/TPS-LWZ8VZDZ-J
ISSN:0897-4756
1520-5002
DOI:10.1021/cm0702262