Large Enhancement of 3-K Phase Superconductivity in the Sr2RuO4–Ru Eutectic System by Uniaxial Pressure

概要

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While the superconducting transition temperature $T_{\text{c}}$ of Sr2RuO4 is 1.5 K, its onset $T_{\text{c}}$ is enhanced as high as 3 K in the Sr2RuO4–Ru eutectic system, which is often referred to as the 3-K phase. We have investigated effects of uniaxial pressure on the non-bulk superconductivity in the 3-K phase. While $T_{\text{c}}$ of pure Sr2RuO4 is known to be suppressed by hydrostatic pressure, a large enhancement of the superconducting volume fraction of the 3-K phase was observed for both out-of-plane and in-plane uniaxial pressures. Especially, under the in-plane pressure, the shielding fraction at 1.8 K of only less than 0.5% at 0 GPa exceeds 40% at 0.4 GPa. Such a large shielding fraction suggests that under the uniaxial pressure interfacial 3-K phase superconductivity penetrates deep into the bulk of Sr2RuO4. The present finding provides a significant implication to the unresolved origin of the enhancement of $T_{\text{c}}$ to 3 K in the Sr2RuO4–Ru eutectic system.
Physical Society of Japanの論文
2009-10-15