Effect of Intrinsic (Closed) Loops Strong Type II Superconductors

B. Rosenstein

《Chinese Journal of Physics》 34卷2S期 (1996/04) Pp. 532-537

並列摘要

Thermal excitation of strong vortex line bending, overhangs, as well as flux loops is expected at significant portions of the phase diagram of high Tc superconductors. I investigate the effect of the flux loops on various properties of these materials. The basic effect is renormalization (loosening) of interaction between vortices due to loops. Interaction between vortex bits is of screened monopole type with penetration depth λ as a cutoff. Interaction between closed loops separated by distance є ＜＜ r ＜＜ λ is that of two dipoles. As is well known this type of interaction interaction leads to renormalization of charge. So the weakening of the intervortex interactions is analogous to polarization due to dipoles and leads to a realistic dependence of superfluid fraction on temperature. The nonlinear resistivity in the Meissner phwe is calculated and compared with recent experiments on YBCO.