Effect of interstitial impurities on the field dependent microwave surface resistance of niobium
Effect of interstitial impurities on the field dependent microwave surface resistance of niobium
复制标题
间隙杂质对铌场相关微波表面电阻的影响
DOI：
10.1063/1.4960801
复制
发表时间：
2016
影响因子：
4
通讯作者：
J. Zasadzinski
中科院分区：
文献类型：
--
作者：
M. Martinello;A. Grassellino;M. Checchin;A. Romanenko;O. Melnychuck;D. Sergatskov;S. Posen;J. Zasadzinski
先前的工作表明，当氮杂质溶解为材料中的间隙时，niobium谐振器的射频表面耐药性大大降低。这种效果归因于随着加速场的增加，马蒂斯 - 贝赛表面电阻的降低。但是，这种现象的微观起源知之甚少。同时，对于此类空腔，通常观察到对捕获磁场的敏感性的增强。在本文中，我们对这些不同的成分进行了系统的研究，该组件与氮化物谐振剂的标准表面处理相比，导致总表面耐药性作为不同水平的溶解氮的函数。将这些结果加在一起，我们能够证明哪种是最佳的表面处理，可最大化超导型niobium谐振器的Q因子，这是腔壁中预期捕获的磁场的函数。这些结果还提供了有关Mattis-Bardeen表面电阻的田间依赖性变化的物理学的见解，以及超导niobium谐振器中捕获的磁涡流引起的磁涡流损失。
Previous work has demonstrated that the radio frequency surface resistance of niobium resonators is dramatically reduced when nitrogen impurities are dissolved as interstitial in the material. This effect is attributed to the lowering of the Mattis-Bardeen surface resistance with increasing accelerating field; however, the microscopic origin of this phenomenon is poorly understood. Meanwhile, an enhancement of the sensitivity to trapped magnetic field is typically observed for such cavities. In this paper, we conduct a systematic study on these different components contributing to the total surface resistance as a function of different levels of dissolved nitrogen, in comparison with standard surface treatments for niobium resonators. Adding these results together, we are able to show which is the optimum surface treatment that maximizes the Q-factor of superconducting niobium resonators as a function of expected trapped magnetic field in the cavity walls. These results also provide insights on the physics behind the change in the field dependence of the Mattis-Bardeen surface resistance, and of the trapped magnetic vortex induced losses in superconducting niobium resonators.