Remanent vortex flux from rotational magnetic states of a polycrystalline superconductor

✍ Scribed by M.K. Hasan; J.S. Kouvel

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 526 KB
• Volume: 258
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(95)00833-0

✦ Synopsis

Rotational magnetization-vector (RMV) measurements on polycrystalline YBa2Cu307 in fixed field 11 at 4.2 K reveal that the vortex flux density in a rotational state consists of a B R component, which rotates rigidly with the sample, and a B component, which stays at a fixed frictional angle OF relative to H. Moreover, B R decreases and ultimately vanishes with increasing H, while B F increases steadily, implying that the vortex pinning forces are broadly distributed in strength. To probe this distribution, we extended the RMV study to include the remanent flux density B rrn resulting from selected rotational states when 11 of various values is removed. It was found that B rrn decomposes analogously into Bit' and Bnn the latter at angle Of!" relative to H removed, and that Bit' is essentially equal to the original B R (before H is remov:d) while Bf!" and Of!" are respectively much smaller and larger than the original B F and OF' These remanence results strongly confinn the existence of a broad pinning force distribution, which is shown to possibly derive from vortex bundling.