Investigating the flux pinning in high temperature superconductors more accurately

To analyze the flux pinning in high temperature superconductors (HTS) more accurately at high temperature such as 77 K, an improved method based on the Dew-Hughes model has been developed. Assumed that core pinning is dominant in HTS, point, surface and volume pinning center in samples caused by normal phase and spatial variations of the Ginzburg parameter (Δκ) have been considered. As examples, the pinning forces of several Bi-2223 silver sheathed (Bi-2223/Ag) tapes have been scaled by traditional single function and improved multi-elementary function. The results indicated that more detail on the pinning mechanism in samples, such as the relative pinning strength of each active pinning center, could be given by the multi-elementary scaling.