Magnetization of low-κ superconductors II. The lower critical field Hc1

✍ Scribed by H.W. Weber; E. Seidl; M. Botlo; C. Laa; H.P. Wiesinger; J. Rammer

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 414 KB
• Volume: 161
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(89)90338-9

✦ Synopsis

In this second part of a series of three publications on the magnetization of low-x superconductors, we present experimental and theoretical results on the lower critical field Hcl. We concentrate on highly pure niobium and vanadium samples. Both materials are type-II superconductors with a first order transition at H¢~. After a brief description of experimental techniques, the theoretical methods used in the present study are outlined. We show that a successful theoretical analysis of experimental data requires the inclusion of both strong-coupling and anisotropy effects. Because of the first order transition at H¢I, the thermodynamics of the interacting vortex lattice has to be solved in order to obtain H¢~. In this way, we achieve excellent agreement between experiment and theory, consistent with our results on other characteristic features of the magnetization in these superconductors. Near To, the validity of Ginzburg-Landau theory is confirmed with high accuracy.