Magnetic field and sheet-current density of a thin type-II superconducting annulus

• Published in: Cryogenics (Guildford) 2017-10, Vol.87, p.12-17
• Main Authors: Babaei-Brojeny, Ali A., Talebi, Amir Hossein
• Format: Article
• Language: English
• Subjects: Annuli; Current density; Flux pinning; Geometrical barrier; Magnetic fields; Magnetic flux; Pinning; Potential barriers; Spatial distribution; Superconducting annulus; Superconductivity; Superconductors
• ISSN: 0011-2275; 1879-2235
• DOI: 10.1016/j.cryogenics.2017.08.007

•Presentation of an efficient method for calculating the magnetic field distribution.•Vertical component of the field drops at the above of washer.•Its radial component goes down to zero on the z axes at the origin.•The effect of geometrical barrier on the field and current distribution is investigated. We investigate theoretically the sheet-current density and total magnetic field (MF) distribution due to a thin, type-II superconducting annulus sample. We have supposed a washer (with the inner and outer radii a and b) carrying sub-critical currents subject to an applied magnetic field. The sample is an ideal washer with no bulk pinning, under two different situations: (a) when flux is focused into the central hole and net current flowing around the washer is zero but the external field Ha=Ba/μ is on, and (b) in the presence of a potential barrier of geometrical origin. Our calculations show that the net MF is maximum in the near-edge region and in the between is weaker than other areas. Moreover, the effect of geometrical barrier on spatial distribution of the field for several superconducting washers of different radii has been analyzed. At the end, we have shown the behavior of field distribution as external field, Ha , is oriented at any arbitrary angle α.