Theory and experiment testing flux-line cutting physics
| Title | Theory and experiment testing flux-line cutting physics |
| Publication Type | Journal Article |
| Year of Publication | 2011 |
| Authors | Clem JR, Weigand M, Durrell JH, Campbell AM |
| Journal Title | Superconductor Science & Technology |
| Volume | 24 |
| Pages | 062002 |
| Date Published | 06 |
| ISBN Number | 0953-2048 |
| Accession Number | ISI:000290472900002 |
| Keywords | critical-state model, films, FORCE, HARD SUPERCONDUCTORS, ii superconductors, losses, moment, rotating magnetic-fields, surface |
| Abstract | We discuss predictions of five proposed theories for the critical state of type-II superconductors accounting for both flux cutting and flux transport (depinning). The theories predict different behaviours for the ratio E-y/E-z of the transverse and parallel components of the in-plane electric field produced just above the critical current of a type-II superconducting slab as a function of the angle of an in-plane applied magnetic field. We present experimental results measured using an epitaxially grown YBCO thin film favouring one of the five theories, i.e. the extended elliptic critical-state model. We conclude that when the current density J is neither parallel nor perpendicular to the local magnetic flux density B, both flux cutting and flux transport occur simultaneously when J exceeds the critical current density J(c), indicating an intimate relationship between flux cutting and depinning. We also conclude that the dynamical properties of the superconductor when J exceeds J(c) depend in detail upon two nonlinear effective resistivities for flux cutting (rho(c)) and flux flow (rho(f)) and their ratio r = rho(c)/rho(f). |
| URL | <Go to ISI>://000290472900002 |
| DOI | 10.1088/0953-2048/24/6/062002 |
| Alternate Journal | Supercond Sci TechSupercond Sci Tech |
