Microscopic Investigation of rf Vortex Nucleation in Nb3Sn Films Using a Near-Field Magnetic Microwave Microscope

Abstract

We use a near-field magnetic microwave microscope to investigate and compare rf vortex nucleation in two superconducting radio-frequency (SRF)-quality Nb3Sn films fabricated by different methods: a conventional vapor-diffused film and an electrochemically plated film followed by thermal annealing, both of which are deposited on Nb substrates. The microscope applies a localized rf magnetic field to the sample surface and measures the resulting third-harmonic response P3f, which is particularly sensitive to rf vortex nucleation triggered by surface defects. Both Nb3Sn films exhibit nontrivial P3f(T) structures below 7 K that display the key signatures associated with rf vortex nucleation at local defects. The electrochemical film additionally shows multiple P3f(T) structures between 14 K and 16 K that are absent in the vapor-diffused sample. Our results highlight the influence of fabrication method on rf vortex penetration properties and demonstrate the utility of third-harmonic response as a local diagnostic tool for surface defects in Nb3Sn films.

arXiv comment9 pages, 8 figures

References in corpus (29)

• Dynamics of vortex penetration, jumpwise instabilities and nonlinear surface resistance of type-II superconductors in strong rf fields
• Advances in Nb3Sn superconducting radiofrequency cavities towards first practical accelerator applications
• Grain-boundary structure and segregation in Nb3Sn coatings on Nb for high-performance superconducting radiofrequency cavity applications
• Time-dependent Ginzburg-Landau treatment of RF Magnetic Vortices in Superconductors: Vortex-Semiloops in a Spatially Nonuniform Magnetic Field
• Analysis of Nb3Sn surface layers for superconducting RF cavity applications
• Role of surface defects and material inhomogeneities for vortex nucleation in superconductors within time-dependent Ginzburg-Landau theory in 2 and 3 dimensions
• Atomic scale analysis of Nb3Sn on Nb prepared by a vapor-diffusion process for superconducting radiofrequency cavity applications
• Microwave Superconductivity
• Doping-Dependent Nonlinear Meissner Effect and Spontaneous Currents in High-Tc Superconductors
• Analysis of Magnetic Vortex Dissipation in Sn-Segregated Boundaries in Nb${}_3$Sn Superconducting RF Cavities
• Performance-defining properties of Nb${}_3$Sn coating in SRF cavities
• Spatially Resolved Nonlinearity Measurements of YBa${}_2$Cu${}_3$O${}_{7-d}$ Bi-crystal Grain Boundaries
• Microwave Nonlinearities of an Isolated Long YBa_2Cu_3O_(7-d) Bi-crystal Grain Boundary
• Microwave measurements of the high magnetic field vortex motion pinning parameters in Nb${}_3$Sn
• $\text{Ab Initio}$ Study of Antisite Defects in Nb${}_3$Sn: Phase Diagram and Impact on Superconductivity
• Phase-sensitive Harmonic Measurements of Microwave Nonlinearities in Cuprate Thin Films
• Nonlinear Near-Field Microwave Microscope For RF Defect Localization in Superconductors
• Nanoscale Nonlinear Radio Frequency Properties of Bulk Nb : Origins of Extrinsic Nonlinear Effects
• High Frequency Nonlinear Response of Superconducting Cavity-Grade Nb surfaces
• Smooth, homogeneous, high-purity Nb3Sn superconducting RF resonant cavity by seed-free electrochemical synthesis
• Nanoscale Electrodynamic Response of Nb Superconductors
• Superconducting properties variation with A15 composition in Nb3Sn
• Near-Field Microwave Magnetic Nanoscopy of Superconducting Radio Frequency Cavity Materials
• Study of Local Nonlinear Properties Using a Near-Field Microwave Microscope
• Surface oxides, carbides, and impurities on RF superconducting Nb and Nb3Sn: A comprehensive analysis
• Microscopic Examination of SRF-quality Nb Films through Local Nonlinear Microwave Response
• Modeling the nanoscale linear response of superconducting thin films measured by a scanning probe microwave microscope
• Thermodynamic route of Nb3Sn nucleation: Role of oxygen
• Microwave Microscope Studies of Trapped Vortex Dynamics in Superconductors