Pinning model derived from resistive measurements on melt processed Bi2Sr2CaCu2O8

✍ Scribed by H.W. Neumüller; G. Ries

• Book ID: 103941585
• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 907 KB
• Volume: 160
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(89)90423-1

✦ Synopsis

On melt processed samples of the 86 K superconductor Bi2Sr2CaCuzOs we have performed resistive measurements in the low field limit B<O. 13 T and 40 KG TG 77 K. The voltage drop is found to rise exponentially with current Eacexpj/j,, which is interpreted in terms of thermal activation of pinned flux lines. An activation energy Cr,( T) 6 90 meV is derived from the transition width j,,( T) and is related to a plausible core pinning interaction of flux lines with normal conducting precipitates. This reproduces the measured j,(B, T) values in the whole regime investigated. We conclude that pinning centers must have a minimum size in order to control flux creep. Finally we demonstrate that conventional summation of the single site pinning forces cannot account for the observed macroscopic depinning current density.