Resistive behavior of high-Tc superconductors with a logarithmiclike pinning potential

Abstract

The flux motion in a superconductor with a periodic logarithmiclike bare pinning potential is investigated. The effective barrier UJ(J) is derived and is shown to bear close resemblance with the related experimental results. The details of the pinning potential profile turn out to have significant influences on the functional form of the effective barrier. The linear response of the superconductor under a small current is analyzed and a slightly new formula is derived for resistivity in the thermally activated flux flow regimes. The distinct regimes for flux creep and flux flow and the crossover in between are treated simultaneously, and the familiar power-law behavior is demonstrated and is further confirmed by examining the dln E/dJ versus H relation. Satisfactory agreement is found between our results and related experimental observations. The experimentally observed field-dependent resistance broadening effect is also reproduced in this model. © 1994 The American Physical Society.