| Autor: |
Oripov, Bakhrom, Bieler, Thomas, Ciovati, Gianluigi, Calatroni, Sergio, Dhakal, Pashupati, Junginger, Tobias, Malyshev, Oleg B., Terenziani, Giovanni, Valente-Feliciano, Anne-Marie, Valizadeh, Reza, Wilde, Stuart, Anlage, Steven M. |
| Rok vydání: |
2019 |
| Předmět: |
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| Zdroj: |
Phys. Rev. Applied 11, 064030 (2019) |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1103/PhysRevApplied.11.064030 |
| Popis: |
Nb Superconducting Radio-Frequency (SRF) cavities are observed to break down and lose their high-Q superconducting properties at accelerating gradients below the limits imposed by theory. The microscopic origins of SRF cavity breakdown are still a matter of some debate. To investigate these microscopic issues temperature and power dependent local third harmonic response was measured on bulk Nb and Nb thin film samples using a novel near-field magnetic microwave microscope between 2.9K-10K and 2GHz-6GHz. Both periodic and non-periodic response as a function of applied RF field amplitude are observed. We attribute these features to extrinsic and intrinsic nonlinear responses of the sample. The RF-current-biased Resistively Shunted Junction (RSJ) model can account for the periodic response and fits very well to the data using reasonable parameters. The non-periodic response is consistent with vortex semi-loops penetrating into the bulk of the sample once sufficiently high RF magnetic field is applied, and the data can be fit to a Time-Dependent Ginzburg-Landau (TDGL) model of this process. The fact that these responses are measured on a wide variety of Nb samples suggests that we have captured the generic nonlinear response of air-exposed Nb surfaces. |
| Databáze: |
arXiv |
| Externí odkaz: |
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