Hybrid Physical-Chemical Vapor Deposition of Ultrathin MgB2 Films on MgO Substrate With High TC and JC

作者：Zhang, Chen^*; Wang, Yue; Wang, Da; Zhang, Yan; Feng, Qing-Rong; Gan, Zi-Zhao

来源：IEEE Transactions on Applied Superconductivity, 2013, 23(3): 7500204.

DOI：10.1109/TASC.2012.2230212

• Critical current density
• magnesium compounds
• superconducting transition temperature
• thin films

MgB2 has been recognized as a candidate material for fabricating superconducting nanowire single photon detectors with the expectation of having an operating temperature of the detector at 10-20 K. Preparation of ultrathin MgB2 films with high superconducting transition temperature T-C is the first crucial step to achieve this goal. Here we present the hybrid physical-chemical vapor deposition of MgB2 superconducting films with thicknesses around 10 nm. The films are epitaxially grown on (111) MgO substrates. The T-C of the films, including for a 6-nm-thick film, is found to be above 34 K, close to the bulk value of MgB2 (39 K). The normal-state resistivity at 42 K of a 10-nm-thick film is shown to be 3.1 mu Omega cm, indicating that the film is relatively clean. The superconducting critical current density J(C) of the films has also been measured on strip lines patterned in the films. The J(C) of the 10-nm-thick film reaches 7.7 x 10(7) A/cm(2) at 2 K, so far the highest value reported for MgB2 films of the same thickness. The high T-C, low residual resistivity, and high J(C) of the ultrathin MgB2 films on MgO substrates suggest that these films have the potential in developing MgB2-based superconducting nanowire single photon detectors or other related superconducting devices.

• 出版日期2013-6
• 单位北京大学