Unconventional superconductivity in NaxCoO2 yH2O

H. Sakurai; K. Takada; T. Sasaki; E. Takayama-Muromachi

doi:10.1016/j.physc.2004.12.017

paper

Unconventional superconductivity in NaxCoO2 yH2O

arXiv:cond-mat/0408426 · doi:10.1016/j.physc.2004.12.017

Abstract

We synthesized powder samples of Na $_{x}$ CoO $_{2} \cdot y$ H $_{2}$ O changing the volume of the water in the hydration process, then investigated their superconducting properties,. It was proved that the volume of water is one of key parameters to obtain a single phase of Na $_{x}$ CoO $_{2} \cdot y$ H $_{2}$ O with good superconducting properties. The transition temperature, $T_{c}$ , of the sample changed gradually while it was stored in the atmosphere of 70% humidity. Superconducting behavior under high magnetic field was very sensitive to $T_{c}$ . $H_{c 2}$ of a high quality sample with high $T_{c}$ seemed very high.

7 pages (3 figures included) and two extra figures (gif), proceedings of TICS'04 & WLTP7