Effect of ruthenium substitution in layered sodium cobaltate Na< i> x</i> CoO< sub> 2</sub>: Synthesis, structural and physical properties - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Solid State Chemistry Année : 2009

Effect of ruthenium substitution in layered sodium cobaltate Na< i> x CoO< sub> 2: Synthesis, structural and physical properties

Résumé

Solid-state synthesis of Na0.71Co1−xRuxO2 compositions shows that ruthenium can be substituted for cobalt in the hexagonal Na0.71CoO2 phase up to x=0.5. The cell expands continuously with increasing ruthenium content. All mixed Co-Ru phases show a Curie-Weiss behaviour with no evidence of magnetic ordering down to 2 K. Unlike the parent phase Na0.71CoO2, ruthenium-substituted phases are all semiconducting. They exhibit high thermoelectric power, with a maximum of 165 μV/K at 300 K for x=0.3. The Curie constant C and Seebeck coefficient S show a non-monotonic evolution as a function of ruthenium content, demonstrating a remarkable interplay between magnetic properties and thermoelectricity. The presence of ruthenium has a detrimental effect on water intercalation and superconductivity in this system. Applying to Ru-substituted phases the oxidative intercalation of water known to lead to superconductivity in the NaxCoO2 system yields a 2-water layer hydrate only for x=0.1, and this phase is not superconducting down to 2 K.

Dates et versions

hal-00942111 , version 1 (04-02-2014)

Identifiants

Citer

Pierre Strobel, Hervé Muguerra, Sylvie Hébert, Elise Pachoud, Claire Colin, et al.. Effect of ruthenium substitution in layered sodium cobaltate Na< i> x CoO< sub> 2: Synthesis, structural and physical properties. Journal of Solid State Chemistry, 2009, 182, pp.1872. ⟨10.1016/j.jssc.2009.04.030⟩. ⟨hal-00942111⟩
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