Home > Research > Publications & Outputs > No interface energy barrier and increased surfa...

Links

Text available via DOI:

View graph of relations

No interface energy barrier and increased surface pinning in low temperature baked niobium

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Published

Standard

No interface energy barrier and increased surface pinning in low temperature baked niobium. / Turner, Dan; Burt, Graeme; Junginger, Tobias.
In: Scientific Reports, Vol. 12, No. 1, 5522, 01.04.2022.

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Harvard

APA

Vancouver

Turner D, Burt G, Junginger T. No interface energy barrier and increased surface pinning in low temperature baked niobium. Scientific Reports. 2022 Apr 1;12(1):5522. doi: 10.21203/rs.3.rs-948318/v1, 10.1038/s41598-022-09023-0

Author

Bibtex

@article{e80322b299c948a7a71d8ed661c89220,
title = "No interface energy barrier and increased surface pinning in low temperature baked niobium",
abstract = "Superconducting Radio-Frequency cavities are currently made out of niobium. Niobium cavities are limited by the magnetic field on the cavity walls due to the entry of vortices at the field of first vortex penetration, Hvp. Low temperature baking in vacuum or low pressure gas atmosphere removes the strong decrease of the quality factor with accelerating gradient (high field Q-slope). Some cavities reach surface magnetic field above the lower critical field Hc1. One hypothesis for this performance increase is that the outer layer affected by the treatments acts as a barrier for vortex penetration (effective bilayer). Using a vibrating sample magnetometer the field of first flux penetration (Hvp) was measured for Nb ellipsoids with various low temperature treatments. All Hvp values were found to be consistent with the lower critical field, Hc1, as predicted for clean niobium. This led to the conclusion that a metastable flux free state above Hc1 cannot be observed in DC magnetometry for low temperature baked niobium unlike for bilayers consisting of two superconductors as previously published. The effect of flux pinning differed significantly between treatments, suggesting that the high field Q-slope mitigation might be related to vortex pinning in the surface of the cavities.",
keywords = "superconductivity, magnetometery, niobium, Superconducting radio frequency, Low temperature baking",
author = "Dan Turner and Graeme Burt and Tobias Junginger",
year = "2022",
month = apr,
day = "1",
doi = "10.21203/rs.3.rs-948318/v1",
language = "English",
volume = "12",
journal = "Scientific Reports",
issn = "2045-2322",
publisher = "Nature Publishing Group",
number = "1",

}

RIS

TY - JOUR

T1 - No interface energy barrier and increased surface pinning in low temperature baked niobium

AU - Turner, Dan

AU - Burt, Graeme

AU - Junginger, Tobias

PY - 2022/4/1

Y1 - 2022/4/1

N2 - Superconducting Radio-Frequency cavities are currently made out of niobium. Niobium cavities are limited by the magnetic field on the cavity walls due to the entry of vortices at the field of first vortex penetration, Hvp. Low temperature baking in vacuum or low pressure gas atmosphere removes the strong decrease of the quality factor with accelerating gradient (high field Q-slope). Some cavities reach surface magnetic field above the lower critical field Hc1. One hypothesis for this performance increase is that the outer layer affected by the treatments acts as a barrier for vortex penetration (effective bilayer). Using a vibrating sample magnetometer the field of first flux penetration (Hvp) was measured for Nb ellipsoids with various low temperature treatments. All Hvp values were found to be consistent with the lower critical field, Hc1, as predicted for clean niobium. This led to the conclusion that a metastable flux free state above Hc1 cannot be observed in DC magnetometry for low temperature baked niobium unlike for bilayers consisting of two superconductors as previously published. The effect of flux pinning differed significantly between treatments, suggesting that the high field Q-slope mitigation might be related to vortex pinning in the surface of the cavities.

AB - Superconducting Radio-Frequency cavities are currently made out of niobium. Niobium cavities are limited by the magnetic field on the cavity walls due to the entry of vortices at the field of first vortex penetration, Hvp. Low temperature baking in vacuum or low pressure gas atmosphere removes the strong decrease of the quality factor with accelerating gradient (high field Q-slope). Some cavities reach surface magnetic field above the lower critical field Hc1. One hypothesis for this performance increase is that the outer layer affected by the treatments acts as a barrier for vortex penetration (effective bilayer). Using a vibrating sample magnetometer the field of first flux penetration (Hvp) was measured for Nb ellipsoids with various low temperature treatments. All Hvp values were found to be consistent with the lower critical field, Hc1, as predicted for clean niobium. This led to the conclusion that a metastable flux free state above Hc1 cannot be observed in DC magnetometry for low temperature baked niobium unlike for bilayers consisting of two superconductors as previously published. The effect of flux pinning differed significantly between treatments, suggesting that the high field Q-slope mitigation might be related to vortex pinning in the surface of the cavities.

KW - superconductivity

KW - magnetometery

KW - niobium

KW - Superconducting radio frequency

KW - Low temperature baking

U2 - 10.21203/rs.3.rs-948318/v1

DO - 10.21203/rs.3.rs-948318/v1

M3 - Journal article

VL - 12

JO - Scientific Reports

JF - Scientific Reports

SN - 2045-2322

IS - 1

M1 - 5522

ER -