Superconducting Properties under Magnetic Field in Na${}_{0.35}$CoO${}_2\cdot 1.3$H${}_2$O Single Crystal

Abstract

We report the in-plane resistivity and magnetic susceptibility of the layered cobalt oxide Na${}_{0.35}$CoO${}_2\cdot 1.3$H${}_2$O single crystal. The temperature dependence of the resistivity shows metallic behavior from room temperature to the superconducting transition temperature $T_c$ of 4.5 K. Sharp resistive transition, zero resistivity and almost perfect superconducting volume fraction below $T_c$ indicate the good quality and the bulk superconductivity of the single crystal. The upper critical field $H_{c2}$ and the coherence length $\xi$ are obtained from the resistive transitions in magnetic field parallel to the c-axis and the $ab$-plane. The anisotropy of $\xi$, ${\xi }_{ab}/{\xi }_c=$ 12 nm/1.3 nm $\simeq$ 9.2, suggests that this material is considered to be an anisotropic three dimensional superconductor. In the field parallel to the $ab$-plane, $H_{c2}$ seems to be suppressed to the value of Pauli paramagnetic limit. It may indicate the spin singlet superconductivity in the cobalt oxide.

4 pages, 4 figures

References in corpus (1)

• Unconventional Upper- and Lower-Critical Fields and Normal-State Magnetic Susceptibility of the Novel Superconducting Compound $N{a}_{0.35}Co{O}_2\cdot 1.3H_{2}O$

Cited by in corpus (1)

• Ferromagnetic fluctuation and possible triplet superconductivity in Na_xCoO_2*yH_2O: Fluctuation-exchange study of multi-orbital Hubbard model