Unconventional superconductivity in Na$_{0.35}$CoO$_{2}\cdot$1.3D$_{2}$O and proximity to a magnetically ordered phase

Y. J. Uemura; P. L. Russo; A. T. Savici; C. R. Wiebe; G. J. MacDougall; G. M. Luke; M. Mochizuki; Y. Yanase; M. Ogata; M. L. Foo; R. J. Cava

paper

Unconventional superconductivity in Na $_{0.35}$ CoO $_{2} \cdot$ 1.3D $_{2}$ O and proximity to a magnetically ordered phase

arXiv:cond-mat/0403031

Abstract

Muon spin relaxation ( $μ$ SR) measurements on the new layered cobalt oxide superconductor Na $_{0.35}$ CoO $_{2} \cdot$ 1.3H $_{2}$ O and its parent, non-superconducting compounds, have revealed unconventional nature of superconductivity through: (1) a small superfluid energy which implies a surprisingly high effective mass of the charge carriers, approximately 100 times the bare electron mass; (2) the superconducting transition temperature $T_{c}$ scaling with the superfluid energy following the correlations found in high- $T_{c}$ cuprate and some other two-dimensional superconductors; (3) an anisotropic pairing without broken time-reversal symmetry; and (4) the proximity of a magnetically ordered insulating phase at Na $_{0.5}$ CoO $_{2}$ below $T_{N}$ = 53 K.

6 pages 4 figures: Contact Y.J. Uemura, E-mail: [email protected]

Unconventional superconductivity in Na0.35​CoO2​⋅1.3D2​O and proximity to a magnetically ordered phase

Abstract

Unconventional superconductivity in Na $_{0.35}$ CoO $_{2} \cdot$ 1.3D $_{2}$ O and proximity to a magnetically ordered phase