Temperature-dependent properties of niobium nitride Josephson tunnel junctions

作者：Alexandre Shoji, Masahiro Aoyagi, S. Kosaka, Fujitoshi Shinoki · 发表于：IEEE Transactions on Magnetics · 年份：1987 · DOI：10.1109/tmag.1987.1064829 · 被引用次数：53 · 研究领域：Physics of Superconductivity and Magnetism、Quantum and electron transport phenomena、Semiconductor Quantum Structures and Devices

We report the electrical properties of all niobium nitride(NbN) Josephson tunnel junctions with magnesium oxide(MgO) films as barriers in the temperature range 4.2-15 K. NbN/MgO/NbN Josephson tunnel junctions have large gap voltages(Vg=4.8-5.4 mV), large products of the maximum critical currents and the normal tunneling resistances(IcRn=3.15-3.35 mV), and small subgap leakage currents(Vm=13-138 mV) at 4.2 K. The junction parameters decreased with increase in temperature, but reasonably large junction parameters(for example, Vg=4.9 mV, IcRn=2.67 mV, and Vm=22 mV) have been obtained even at 9 K. The magnetic penetration depth in NbN electrodes has been measured up to 15 K using two-junction interferometers which consist of NbN/MgO/NbN junctions, NbN ground planes, and NbN control lines.