Ac-losses of superconducting Bi-2223 tapes with two different time constants

✍ Scribed by Curt Schmidt; Ludovit Krempasky

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 350 KB
• Volume: 42
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/s0011-2275(02)00079-6

✦ Synopsis

Ac-loss and time constant measurements were performed with Bi-2223 tape conductors in Ag matrix at 4.2 K and at 77 K. The frequency dependence of the loss curve shows the expected maximum at xs ¼ 1. In some cases the loss curve goes through a minimum in the higher frequency range and then increases again, with a possible second maximum. It is shown that this second increase is explained by eddy currents in the silver matrix, which are described by a second time constant # ( s. Both time constants, s and # can be seen in time constant measurements. The full theoretical description of time constant and loss measurements is given using a slab model. The agreement with the measurements is very good in parallel field orientation where the slab model is a good approach, and it is still a valuable approach in perpendicular field.