Figure 5
Normalized values of the ground-state critical current density, \({J}_{c}^{n}\) (black), surface current density, \({J}_{s}^{n}\) (red), and surface field, \({B}_{s}^{n}\) (blue), for type I and type II superconductors in films or round wires plotted versus normalized conductor dimension b/λ for films and a/2λ for round wires. Values are calculated using Eqs 11 and 12, 13 and 15. For anisotropic superconductors \(\gamma {B}_{s}^{n}\) is plotted instead of \({B}_{s}^{n}\), where γ = λ c /λ ab –see text. When b ≫ λ the blue \({B}_{s}^{n}\) data points more or less exactly superpose the red \({J}_{s}^{n}\) data points which are made slightly larger to be seen. For b ≪ λ the black \({J}_{c}^{n}\) data points sit exactly under the red \({J}_{s}^{n}\) data points. The figure shows that for all size scales the critical surface current density, J s , always equals the critical field divided by μ 0λ. \({B}_{s}^{n}\) for the three iron pnictides is shown in green to identify them across the entire range.
