Near-Field Microwave Magnetic Nanoscopy of Superconducting Radio Frequency Cavity Materials

Abstract

A localized measurement of the RF critical field on superconducting radio frequency (SRF) cavity materials is a key step to identify specific defects that produce quenches of SRF cavities. Two new measurements are performed to demonstrate these capabilities with a novel near-field scanning probe microwave microscope. The first is a third harmonic nonlinear measurement on a high Residual- Resistance-Ratio bulk Nb sample showing strong localized nonlinear response for the first time, with surface RF magnetic field $B_{surface}\sim 10^2$ $mT$. The second is a raster scanned harmonic response image on a high quality $Mg{B}_2$ thin film demonstrating a quench defect-free surface over large areas.

4 pages, 4 figures

References in corpus (3)

• Doping-Dependent Nonlinear Meissner Effect and Spontaneous Currents in High-Tc Superconductors
• Microwave Nonlinearities of an Isolated Long YBa_2Cu_3O_(7-d) Bi-crystal Grain Boundary
• Modeling the nanoscale linear response of superconducting thin films measured by a scanning probe microwave microscope

Cited by in corpus (9)

• Time-dependent Ginzburg-Landau treatment of RF Magnetic Vortices in Superconductors: Vortex-Semiloops in a Spatially Nonuniform Magnetic Field
• High Frequency Nonlinear Response of Superconducting Cavity-Grade Nb surfaces
• Nanoscale Nonlinear Radio Frequency Properties of Bulk Nb : Origins of Extrinsic Nonlinear Effects
• Imaging the paramagnetic nonlinear Meissner effect in nodal gap superconductor
• Microscopic Examination of SRF-quality Nb Films through Local Nonlinear Microwave Response
• Implementing Microwave Impedance Microscopy in a Dilution Refrigerator
• MilliKelvin microwave impedance microscopy in a dry dilution refrigerator
• Microwave Microscope Studies of Trapped Vortex Dynamics in Superconductors
• Microscopic Investigation of rf Vortex Nucleation in Nb3Sn Films Using a Near-Field Magnetic Microwave Microscope