Proceedings of the 20th International Conference on RF Superconductivity
SRF2021: 20th International Conference on RF Superconductivity, June 27- July 2, 2021, East Lansing, Michigan
In the quest for alternative superconducting materials to bring accelerator cavity performance beyond the bulk niobium (Nb) intrinsic limits, a promising concept uses superconductor-insulator-superconductor (SIS) thin film structures that allows magnetic flux shielding in accelerator cavities to higher fields . Candidate materials for such structures are NbTiN as the superconductor and AlN as the insulator. We have demonstrated high quality NbTiN and AlN deposited by reactive DC magnetron sputtering (DCMS), both for individual layers and multilayers. Interface quality has been assessed for bilayer stacks with 250 nm NbTiN layers and AlN thicknesses from 30 nm down to1 nm. These SIS structures show continued sharp interfaces with total average roughness under 2 nm. The Hfp enhancement of the films will be examined with a 3rd harmonic magnetometry. The system is being designed and built in a continuing collaboration with CEA Saclay. It can measure 25 to 50 mm samples on a temperature controlled stage. This contribution presents an overview of the design of the 3rd harmonic magnetometer and the material properties assessment of standalone films and multilayer nanostructures.
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Original Publication Citation
Beverstock, D. R., Antoine, C. Z., Delayen, J. R., Manos, D., Senevirathne, I. H., Spradlin, J. K., & Valente-Feliciano, A.-M. (2022). Samples for 3rd harmonic magnetometry assessment of NbTiN-based SIS structures. In K. Saito, T. Xu, N. Sakamoto, A. Lesage, & V.R.W. Schaa (Eds.), Proceedings of the 20th International Conference on RF Superconductivity (pp. 164-166). JACoW. https://doi.org/10.18429/JACoW-SRF2021-SUPTEV016
Beverstock, D.R.; Antoine, C.Z.; Delayen, Jean R.; Manos, D.; Senevirathne, Iresha Harshani; Spradlin, J. K.; and Valente-Feliciano, A-M., "Samples for 3rd Harmonic Magnetometry Assessment of NbTiN-Based SIS Structures" (2022). Physics Faculty Publications. 728.