arXiv subjects

S. Bayrakci

Publications and source records attributed to S. Bayrakci.

2 recordsLinked to original sources

arXiv2007

Doping induced magnetic clusters and Co spin state transition in Na_xCoO_2 with 0.78<x<.97

By muon spin rotation we investigated the magnetic properties of a series of highly Na doped NaxCoO2 single crystals with 0.78(1) 0.04 until they yield a bulk magnetic state near x=0.78. Evidence for a strong (likely geometrical) frustration of the magnetic order is obtained from the anomalous doping dependence of the spin fluctuation rate (above the ordering temperature) which is strongly enhanced at x=0.78 as compared to x=0.97.

cond-mat.supr-con↗

arXiv2004

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

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 $\rm T_N$.

cond-mat.str-el↗