کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1329260 | 978899 | 2009 | 7 صفحه PDF | دانلود رایگان |

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.
Grapical AbstractEffect of ruthenium substitution on thermoelectric power in Na0.71Co1−xRuxO2 (left) and on low-temperature ac susceptibility in hydrated derivative (right).Figure optionsDownload as PowerPoint slide
Journal: Journal of Solid State Chemistry - Volume 182, Issue 7, July 2009, Pages 1872–1878