26th Australian Institute of Physics Congress and the Australian and New Zealand Conference on Optics and Photonics

Development and Evaluation of Superconducting Coatings for RF Cavities Operating in Magnetic Fields

Not scheduled

20m

Belinda Hutchinson Building (The University of Sydney )

Contributed Oral AIP | Condensed Matter & Materials (CMM)

Description

Superconducting RF cavities operating in magnetic fields require low loss surface coatings that maintain high performance under cryogenic conditions. These systems are relevant to a range of applications, including accelerator technology, quantum devices, and axion dark matter searches. A key challenge is the development of reliable fabrication routes and a consistent evaluation framework for superconducting coatings across different material platforms.
This work develops multiple thin film deposition routes. Pulsed DC reactive magnetron sputtered NbTiN thin films are used as a mature experimental platform, while REBCO based thin films are pursued in parallel as a higher performance candidate system.
NbTiN is deposited using pulsed DC reactive magnetron sputtering, while REBCO is sputtered using a combination of RF and DC magnetron sputtering. The sputtering parameter space is systematically explored to identify a stable deposition window, with emphasis placed on optimising the deposition parameters to determine film quality and superconducting behaviour.
A multi modal characterisation strategy is employed, combining X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), optical profilometry, and four point probe measurements. Together, these techniques provide a coupled framework linking deposition conditions to structural, compositional, morphological properties, enabling systematic process refinement.
Final evaluation is done through cryogenic measurements in a dilution refrigerator. Superconducting behaviour is confirmed around 5 K for NbTiN. High magnetic field testing will be completed prior to presentation.
Overall, this work establishes a methodology for the fabrication and evaluation of superconducting coatings for RF cavities in magnetic fields, developed across both NbTiN thin films and REBCO based coated conductor systems. NbTiN serves as the initial experimental platform due to its greater process maturity, while REBCO is pursued in parallel as a higher performance candidate for future low loss superconducting devices in precision measurement and dark matter detection applications.