Unconventional charge ordering in Na0.70CoO2 below 300 Kстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:We present the results of measurements of the dc-magnetic susceptibility χ(T) and the 23Na-NMR response of Na 0.70CoO2 at temperatures between 50 and 340 K. The χ(T) data suggest that for T>75 K, the Co ions adopt an effective configuration of Co3.4+. The 23Na-NMR response reveals pronounced anomalies near 250 and 295 K, but no evidence for magnetic phase transitions is found in χ(T). Our data suggest the onset of a dramatic change in the Co 3d-electron spin dynamics at 295 K. This process is completed at 230 K. Our results may be interpreted as evidence for either a tendency to electron localization or an unconventional charge-density-wave phenomenon within the Co 3d electron system near room temperature.