posted on 2018-07-25, 08:37authored byStuart Wilde, Reza Valizadeh, O.B. Malyshev, G.B.G. Stenning, T. Sian, Boris Chesca
We performed a systematic investigation of the dc magnetic properties of superconducting niobium thin
films deposited by high power impulse magnetron sputtering (HiPIMS) as a function of the main deposition parameters: the temperature, T, of the heated substrate and the applied dc bias voltage, V, during the sputtering process. The measured dc magnetization curves between 0 and 1000 mT were used to calculate the relative volume of each sample into which the applied magnetic field had penetrated, ðΔV=VÞM. The sample deposited at 700°C with −80 V biased substrate exhibited the least penetration by the magnetic field. ðΔV=VÞM appeared to be highly dependent on the bias voltage at both room temperature and 500°C; however, a broad range of bias voltages showed comparatively similar results at increased temperatures of 700°C. Samples deposited at 700°C exhibit smaller upper critical fields, HC2, than samples deposited at room temperature and 500°C, with the lower temperatures exhibiting a greater dependency on the applied bias. The films deposited at 700°C also display a more stable magnetization curve suggesting that an enhanced flux pinning was achieved when compared to lower temperatures. Consequently, films with stable pinning were found to have the most repeatable dc magnetic behavior. Our results are particularly relevant to the superconducting radio-frequency accelerator scientific community where thin films have been suggested as a technology which may ultimately surpass the performance of bulk niobium. They are also relevant to the fundamental area of superconducting thin films and any applied area where thin films produced by HiPIMS are used, such as superconducting electronics.
History
School
Science
Department
Physics
Published in
Physical Review Special Topics. Accelerators and Beams
Volume
21
Pages
073101 - 073101
Citation
WILDE, S. ... et al, 2018. dc magnetometry of niobium thin film superconductors deposited using high power impulse magnetron sputtering. Physical Review Accelerators and Beams, 21 (7), 073101.
Publisher
American Physical Society
Version
VoR (Version of Record)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/ by/4.0/
Acceptance date
2018-06-16
Publication date
2018-07-20
Notes
This is an Open Access Article. It is published by the American Physical Society under the Creative Commons Attribution 4.0 International Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/