TY  - CONF
AU  - Asaduzzaman, M.
AU  - Junginger, T.
AU  - Laxdal, R.E.
AU  - McFadden, R.M.L.
AU  - Thoeng, E.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Muon Spin Rotation Studies of Bilayer Superconductors and Low Temperature Baked Niobium
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - Muon spin rotation (muSR) results have shown that vortex penetration into Nb can be delayed up to the superheating field Hsh by a single layer of a material with larger London penetration depth. For low temperature baked (LTB) Nb an increase in the vortex penetration field Hvp has also been observed. While clearly exceeding the lower critical field Hc1, Hvp was found to remain significantly below Hsh for LTB niobium (Superconductor Science and Technology 30 (12), 125012). Further, magnetometry experiments suggested that there is no interface barrier in LTB Nb and that the apparent Hvp increase as observed by muSR was due to surface pinning (Scientific Reports 12 (1), 5522). By varying the implantation depth of ~4.1 MeV muons using moderating foils, new muSR measurements confirm that the apparent Hvp increase in LTB Nb is indeed due to surface pinning, while for a Nb₃Sn/Nb bilayer we find an interface barrier for flux penetration. These results confirm the potential of using superconducting bilayers to achieve a flux free Meissner state up to the superheating field of the substrate.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 62
EP  - 66
KW  - interface
KW  - experiment
KW  - cavity
KW  - polarization
KW  - niobium
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-MOPMB005
UR  - https://jacow.org/srf2023/papers/mopmb005.pdf
ER  - 

TY  - CONF
AU  - Thoeng, E.
AU  - Asaduzzaman, M.
AU  - Dunsiger, S.R.
AU  - Fujimoto, D.
AU  - Junginger, T.
AU  - Karner, V.L.
AU  - Kiefl, R.
AU  - Kolb, P.
AU  - Laxdal, R.E.
AU  - Li, R.
AU  - MacFarlane, W.A.
AU  - McFadden, R.M.L.
AU  - Morris, G.
AU  - Stachura, M.
AU  - Ticknor, J.O.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - First Results from beta-SRF- Testing SRF Samples at High Parallel Field
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - The new ¿-SRF facility at TRIUMF has recently been commissioned. A new 1 m extension has been added to an existing ¿-NMR beamline with a large Helmholtz coil to produce fields up to 200 mT parallel to sample surfaces. The ¿-NMR technique allows depth dependent characterization of the local magnetic field in the first 100 nm of the sample surface making the probe ideal for studying Meissner screen- ing in heat treated Niobium or layered SRF materials. First measurements of Meissner screening at fields up to 200 mT have been analyzed. The results show clear differences in the Meissner screening of baseline treatments compared to mid-T baked (O-doped) Niobium.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 374
EP  - 379
KW  - SRF
KW  - polarization
KW  - experiment
KW  - niobium
KW  - ISAC
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUIXA04
UR  - https://jacow.org/srf2023/papers/tuixa04.pdf
ER  -