AC losses in macroscopic thin-walled superconducting cylinders

authored by: M. I. Tsindlekht, V. M. Genkin, I. Felner, F. Zeides, N. Katz, Gazi, Chromik, O. V. Dobrovolskiy
Abstract: Measurements of the ac response represent a valuable method for probing the properties of superconductors. In the surface superconducting state (SSS), a current exceeding the surface critical current I _c leads to breakdown of SSS and penetration of external magnetic field into the sample bulk. An interesting free-of-bulk system in SSS is offered by thin-walled cylinders. According to the full penetration of magnetic flux (FPMF) model, each time the instant value of an ac field is equal to a certain critical value, the ac susceptibility χ will exhibit jumps as a function of the ac field amplitude H _ac because of the periodic destruction and restoration of SSS in the cylinder wall. Here we study the low-frequency (128-8192 Hz) ac response of thin-walled niobium cylinders under superimposed dc and ac magnetic fields applied parallel to the cylinder axis. In contrast to the FPMF model predictions, experiments reveal a smooth χ(H _ac) dependence. To explain the experimental observations, we propose a phenomenological partial penetration magnetic flux (PPMF) model, which assumes that after restoration of the superconducting state, the magnetic fields inside and outside the cylinder are unequal and the magnitude of the penetrating flux is random for every penetration. This model fits very well the experimental data on the temperature dependence of the first harmonic χ ₁ for any dc field and ac amplitude.
External Organisation(s): Hebrew University of Jerusalem (HUJI)
Slovak Academy of Sciences
Technische Universität Braunschweig
University of Vienna
Type: Article
Journal: Physica scripta
Volume: 99
ISSN: 0031-8949
Publication date: 01.08.2024
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Atomic and Molecular Physics, and Optics, Mathematical Physics, Condensed Matter Physics
Electronic version(s): https://doi.org/10.1088/1402-4896/ad5ecc (Access: Open)

BibTeX

@article{f9b378a903b74e91a4df13bcdfec2f8b,
title = "AC losses in macroscopic thin-walled superconducting cylinders",
abstract = "Measurements of the ac response represent a valuable method for probing the properties of superconductors. In the surface superconducting state (SSS), a current exceeding the surface critical current I c leads to breakdown of SSS and penetration of external magnetic field into the sample bulk. An interesting free-of-bulk system in SSS is offered by thin-walled cylinders. According to the full penetration of magnetic flux (FPMF) model, each time the instant value of an ac field is equal to a certain critical value, the ac susceptibility χ will exhibit jumps as a function of the ac field amplitude H ac because of the periodic destruction and restoration of SSS in the cylinder wall. Here we study the low-frequency (128-8192 Hz) ac response of thin-walled niobium cylinders under superimposed dc and ac magnetic fields applied parallel to the cylinder axis. In contrast to the FPMF model predictions, experiments reveal a smooth χ(H ac) dependence. To explain the experimental observations, we propose a phenomenological partial penetration magnetic flux (PPMF) model, which assumes that after restoration of the superconducting state, the magnetic fields inside and outside the cylinder are unequal and the magnitude of the penetrating flux is random for every penetration. This model fits very well the experimental data on the temperature dependence of the first harmonic χ 1 for any dc field and ac amplitude.",
keywords = "ac response, critical fields, superconductivity, thin-walled cylinders",
author = "Tsindlekht, {M. I.} and Genkin, {V. M.} and I. Felner and F. Zeides and N. Katz and Gazi and Chromik and Dobrovolskiy, {O. V.}",
note = "Publisher Copyright: {\textcopyright} 2024 The Author(s). Published by IOP Publishing Ltd.",
year = "2024",
month = aug,
day = "1",
doi = "10.1088/1402-4896/ad5ecc",
language = "English",
volume = "99",
journal = "Physica scripta",
issn = "0031-8949",
publisher = "IOP Publishing Ltd.",
number = "8",
}