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Bulk antiferromagnetism in $\bf Na_{0.82}CoO_2$ single crystals

S. Bayrakci·C. Bernhard·D. P. Chen·B. Keimer·R. K. Kremer·P. Lemmens·C. T. Lin·C. Niedermayer·J. Strempfer
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Abstract

Susceptibility, specific heat, and muon spin rotation measurements on high-quality single crystals of $\rm Na_{0.82}CoO_2$ have revealed bulk antiferromagnetism with Néel temperature $\rm T_N = 19.8 \pm 0.1$ K and an ordered moment perpendicular to the $\rm CoO_2$ layers. The magnetic order encompasses nearly 100% of the crystal volume. The susceptibility exhibits a broad peak around 30 K, characteristic of two-dimensional antiferromagnetic fluctuations. The in-plane resistivity is metallic at high temperatures and exhibits a minimum at $\rm T_N$.

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S. Bayrakci, C. Bernhard, D. P. Chen, B. Keimer, R. K. Kremer, P. Lemmens, C. T. Lin, C. Niedermayer, J. Strempfer. 2004-03-31. Bulk antiferromagnetism in $\bf Na_{0.82}CoO_2$ single crystals. https://doi.org/10.1103/physrevb.69.100410

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