| AVS 66th International Symposium & Exhibition | |
| Vacuum Technology Division | Monday Sessions |
| Session VT-MoA |
| Session: | Gas Dynamics, Surface Science for Accelerators, and Ultra-Clean Vacuum Systems |
| Presenter: | David Beverstock, Jefferson Lab |
| Authors: | D.R. Beverstock, Jefferson Lab A.-M. Valente-Feliciano, Jefferson Lab V.N. Smolyaninova, Towson University M.J. Kelley, The College of William and Mary |
| Correspondent: | Click to Email |
Approaching the bulk Nb material RF performance limits has urged development of alternative superconducting materials for superconducting radio frequency (SRF) accelerator cavities for further performance enhancement. A promising theory has predicted that thin film structures of superconductor-insulator-superconductor (SIS) [1] can delay magnetic flux penetration in accelerator cavities to higher fields. A candidate superconductor for the SIS structures is NbTiN. A few key aspects of SIS structures development are high quality individual layers, sharp interfaces and optimum thickness for first flux penetration (Hfp) delay. High quality monocrystalline NbTiN films are deposited by reactive DC magnetron sputtering. In a parallel development, interface quality was assessed by depositing bilayers of 3 nm NbTiN with ~1 nm AlN repeated up to 16 times with no increase in roughness of the structure. The stacked layers form a metamaterial, which could exhibit Tc greater than bulk NbTiN [2]. This contribution presents the characterization of the surface, material and superconductivity of NbTiN with concentration on the Hfp enhancement for 200 to 5 nm films and multilayer nanostructures.
References:
[1] Gurevich, Alex. "Maximum screening fields of superconducting multilayer structures." AIP Advances 5.1 (2015): 017112.
[2] Smolyaninova, Vera N., et al. "Enhanced superconductivity in aluminum-based hyperbolic metamaterials." Scientific reports 6 (2016): 34140.
Acknowledgements:
*Work supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and by DARPA grant W911NF1710348.