Direct link between low-temperature magnetism and high-temperature sodium order in Na(x)CoO(2)

作者：Schulze T F^*; Haefliger P S; Niedermayer Ch; Mattenberger K; Bubenhofer S; Batlogg B

来源：Physical Review Letters, 2008, 100(2): 026407.

DOI：10.1103/PhysRevLett.100.026407

We prove the direct link between low-temperature (T) magnetism and high-T Na(+) ordering in Na(x)CoO(2) using the example of a so far unreported magnetic transition at 8 K which involves a weak ferromagnetic moment. The 8 K feature is characterized in detail and its dependence on a diffusive Na(+) rearrangement around 200 K is demonstrated. Applying muons as local probes this process is shown to result in a reversible phase separation into distinct magnetic phases that can be controlled by specific cooling protocols. Thus the impact of ordered Na(+) Coulomb potential on the CoO(2) physics is evidenced opening new ways to experimentally revisit the Na(x)CoO(2) phase diagram.

• 出版日期2008-1-18