Evaluation of film thickness dependency of the reversible fluxoid motion in the third harmonic voltage method

✍ Scribed by T. Yoshida; M. Shibata; M. Kiuchi; E.S. Otabe; T. Matsushita; M. Futamura; H. Konishi; S. Miyata; A. Ibi; Y. Yamada; Y. Shiohara

• Book ID: 104082735
• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 210 KB
• Volume: 463-465
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2007.01.058

✦ Synopsis

Significant overestimation of the critical current density J c is found for the third harmonic voltage measurement method for thin YBCO superconductors. This is caused by a reversible flux motion in pinning potentials, which is known to be significant for superconductors of thickness comparable to or smaller than Campbell's AC penetration depth. In this paper the effect of reversible flux motion on the estimation of J c by this method with different thicknesses is also theoretically investigated by using the Campbell model for the forcedisplacement characteristics of flux lines. Although the factor of overestimation can be approximately explained by the Campbell model, agreement is not satisfactory. It is considered that the variation in the flux motion from reversible to irreversible states seems to take place much faster than assumed in the Campbell model.