Effect of vortex hotspots on the radio-frequency surface resistance of superconductors
Effect of vortex hotspots on the radio-frequency surface resistance of superconductors
复制标题
涡流热点对超导体射频表面电阻的影响
DOI：
10.1103/physrevb.87.054502
复制
发表时间：
2013
影响因子：
3.7
通讯作者：
A. G. A. Ciovati
中科院分区：
文献类型：
--
作者：
A. G. A. Ciovati
我们介绍了被困的涡旋束产生的热点的详细实验和理论投资，它们对低温下的射频抗性（RF）表面电阻R {sub s}的影响。温度映射和激光扫描2.36毫米厚的NB板掺入3.3 GHz NB谐振器腔中，由超氟He冷却在2 K时，揭示了热点的空间尺度和温度分布，并表明它们可以移动或分裂。扫描激光束产生的热梯度。包含约10 {sup 6}涡流分布在约0.1-1 cm上的区域。由RF Meissner电流驱动的涡流。并产生r {sub s}对RF场放大器H {sub p}的显着依赖性，这可能对粒子加速器中使用的RF共鸣腔和量子计算和照片中使用的薄膜结构具有重要意义检测器。«少
We present detailed experimental and theoretical investigations of hotspots produced by trapped vortex bundles and their effect on the radio-frequency (rf) surface resistance R{sub s} of superconductors at low temperatures. Our measurements of R{sub s}, combined with the temperature mapping and laser scanning of a 2.36-mm-thick Nb plate incorporated into a 3.3-GHz Nb resonator cavity cooled by the superfluid He at 2 K, revealed spatial scales and temperature distributions of hotspots and showed that they can be moved or split by thermal gradients produced by the scanning laser beam. These results, along with the observed hysteretic field dependence of R{sub s} which can be tuned by the scanning laser beam, show that the hotspots in our Nb sample are due to trapped vortex bundles which contain ∼10{sup 6} vortices spread over regions ∼0.1–1 cm. We calculated the frequency dependence of the rf power dissipated by oscillating vortex segments trapped between nanoscale pinning centers, taking into account all bending modes and the nonlocal line tension of the vortex driven by rf Meissner currents. We also calculated the temperature distributions caused by trapped vortex hotspots, and suggested a method of reconstructing the spatial distribution of vortex dissipation sources from the observed temperaturemore » maps. Vortex hotspots can dominate the residual surface resistance at low temperatures and give rise to a significant dependence of R{sub s} on the rf field amplitude H{sub p}, which can have important implications for the rf resonating cavities used in particle accelerators and for thin-film structures used in quantum computing and photon detectors.« less