The role of the water molecules in novel superconductor, Na$_{0.35}$CoO$_{2}\cdot$1.3H$_{2}$O

H. Sakurai; K. Takada; F. Izumi; D. A. Dilanian; T. Sasaki; E. Takayama-Muromachi

doi:10.1016/j.physc.2003.12.033

paper

The role of the water molecules in novel superconductor, Na $_{0.35}$ CoO $_{2} \cdot$ 1.3H $_{2}$ O

arXiv:cond-mat/0310717 · doi:10.1016/j.physc.2003.12.033

Abstract

In order to investigate the role of the water molecules in Na $_{0.35}$ CoO $_{2} \cdot$ 1.3H $_{2}$ O, we synthesized superconducting Na $_{0.35}$ CoO $_{2} \cdot$ 1.3H $_{2}$ O and nonsuperconducting Na $_{0.35}$ CoO $_{2} \cdot$ 0.7H $_{2}$ O, and measured their normal-state magnetic susceptibilities. The susceptibility of Na $_{0.35}$ CoO $_{2} \cdot$ 1.3H $_{2}$ O has an enhancement below ~150 K probably caused by ferromagnetic fluctuation, whereas no such enhancement was observed in Na $_{0.35}$ CoO $_{2} \cdot$ 0.7H $_{2}$ O. The water molecules in Na $_{0.35}$ CoO $_{2} \cdot$ 1.3H $_{2}$ O may work to shield random coulomb potential of the Na ions with smoother potential at the CoO $_{2}$ layer. This effect may account for the appearance of superconductivity in Na $_{0.35}$ CoO $_{2} \cdot$ 1.3H $_{2}$ O.

3 figures (and 1 table). Proceedings of ISS2003 (Physica C)

The role of the water molecules in novel superconductor, Na0.35​CoO2​⋅1.3H2​O

Abstract

The role of the water molecules in novel superconductor, Na $_{0.35}$ CoO $_{2} \cdot$ 1.3H $_{2}$ O