Anomalous suppression of superconductivity in Zn-substitutedBi2Sr2Ca1−xYx(Cu1−yZny)2O8+δ

We have found an anomalous suppression of superconductivity at $x=0.30\mathrm{}–0.35$, where $p$ (the hole concentration per Cu) $\sim \hspace{0.5em}1/8$, in the partially Zn-substituted compound ${\mathrm{Bi}}_2{\mathrm{Sr}}_2{\mathrm{Ca}}_{1-x}{\mathrm{Y}}_x({\mathrm{Cu}}_{1-y}{\mathrm{Zn}}_y{)}_2{\mathrm{O}}_{8+\delta }$ with $y=0.02\mathrm{}–0.03$. In these samples with $p\sim 1/8$ and $y=0.02\mathrm{}–0.03$, transport properties such as electrical resistivity and thermoelectric power exhibit less metallic behavior than usual. There is a possibility that a kind of order of holes and/or spins is stabilized owing to pinning by Zn, as in the La-based cuprate. It is likely that the so-called “1/8 problem” is not only characteristic of the La-based cuprate but also common to all high-$T_c$ cuprates including ${\mathrm{CuO}}_2$ planes in their crystal structures.