Josephson tunneling properties in MgB2/AlN/NbN tunnel junctions
Josephson tunneling properties in MgB2/AlN/NbN tunnel junctions
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MgB2/AlN/NbN 隧道结中的约瑟夫森隧道特性
DOI：
10.1063/1.1511827
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发表时间：
2002
影响因子：
3.2
通讯作者：
Zhen Wang
中科院分区：
文献类型：
--
作者：
A. Saito;A. Kawakami;H. Shimakage;H. Terai;Zhen Wang
我们报告的约瑟夫森隧道结与生长的MgB 2薄膜的制作和约瑟夫森隧道结的特性。在同一真空运行中，在蓝宝石（0001）衬底上连续沉积了MgB 2/AlN/NbN三层。在250 °C的低衬底温度下使用常规溅射方法制备了生长的MgB 2薄膜，并且在环境衬底温度下通过反应溅射沉积AlN隧道势垒和NbN对电极。 MgB 2薄膜的Tc为28 K。结表现出明显的约瑟夫森隧穿特性，具有明显的超电流，间隙电压，和小的亚间隙漏电流。这些结的正常电阻有一个理想的依赖于结面积和AlN势垒厚度。测量了差距电压与温度的关系和超导电流与外加直流磁场的关系，研究了MgB 2/AlN/NbN薄膜的约瑟夫森隧穿行为。
We report on the fabrication of Josephson tunnel junctions with as-grown MgB2 thin films and on the Josephson tunneling properties of the junctions. MgB2/AlN/NbN trilayers were continuously deposited on sapphire (0001) substrates in the same vacuum run. The as-grown MgB2 thin films were fabricated using the conventional sputtering method at the low-substrate temperature of 250 °C, and the AlN tunnel barrier and the NbN counter electrode were deposited by reactive sputtering at the ambient substrate temperature. The Tc of the MgB2 thin films was 28 K. The junctions demonstrated clear Josephson tunneling characteristics with evident supercurrents, gap voltages, and small subgap leakage currents. The normal resistance of these junctions had an ideal dependence on the junction areas and on the AlN-barrier thickness. The temperature dependence of the gap voltages and the external dc magnetic-field dependence of the supercurrents were measured to investigate the Josephson tunneling behaviors in the MgB2/AlN/NbN...