当研究室が初めてエピタキシャル膜の成長に成功した銅酸化物超伝導(Pb,Cu)Sr2(Y,Ca)Cu2O7 (Pb1212)のc軸固有ジョセフソン特性について報告した論文が日本物理学会の学術誌、Journal of Physical Society of Japanに掲載されました。
A quasi-two-dimensional electron system resulting from a layered crystal structure is a common feature of high-temperature superconductors. In such a system, an interlayer Josephson coupling is responsible for bulk superconductivity. However, materials of interest are limited for Bi-based cuprates which have underdamped and systematically controllable interlayer Josephson junctions. Here, we report the c-axis transport properties and an interlayer Josephson coupling of a 1212-type cuprate superconductor which have not been well studied so far. We demonstrate an underdamped Josephson coupling between superconducting CuO2 double-layers through a chemically controllable (Pb,Cu)–O barrier layer. Broadly tunable Josephson properties through a chemical substitution demonstrated in this work in conjunction with a rich variety of barrier layers for 1212-type cuprates can potentially offer a material breakthrough in the research field of intrinsic Josephson junctions.