Universal Phase Diagram and Reentrant Superconductivity of $Bi$layer Hydrated Na${}_x$CoO${}_2\cdot y$H${}_2$O

Hiroto Ohta, Chishiro Michioka, Yutaka Itoh +1

We report duration dependence of superconductivity in a 43 \% humidity atmosphere and ${}^{59}$Co nuclear quadrupole resonance (NQR) of polycrystalline samples of $bi$layer hydrated…