Nanoscale nonlinear radio frequency properties of bulk Nb: Origins of extrinsic nonlinear effects

Article

关键词: MICROWAVE;    SURFACE;    SUPERCONDUCTIVITY;    ELECTRODYNAMICS;    INTERMODULATION;    NIOBIUM;    DRIVEN;   

DOI  :  10.1103/PhysRevB.92.134513

来源: SCIE

【 摘 要 】

The performance of niobium-based superconducting radio frequency (SRF) particle-accelerator cavities can be sensitive to localized defects that give rise to quenches at high accelerating gradients. In order to identify these material defects on bulk Nb surfaces at their operating frequency and temperature, a wide-bandwidth microwave microscope with localized and strong RF magnetic fields is developed by integrating a magnetic write head into the near-field microwave microscope to enable mapping of the local electrodynamic response in the multi-GHz frequency regime at cryogenic temperatures. This magnetic writer demonstrates a localized and strong RF magnetic field on bulk Nb surface with B-surface > 10(2) mT and submicron resolution. By measuring the nonlinear response of the superconductor, nonlinearity coming from the nanoscale weak-link Josephson junctions due to the contaminated surface in the cavity-fabrication process is demonstrated.

【 授权许可】

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