Theory and experiment testing flux-line cutting physics
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{sub y}/E{sub 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{sub c}, indicating an intimate relationship between flux cutting and depinning. We also conclude that the dynamical properties of the superconductor when J exceeds J{sub c} depend in detail upon two nonlinear effective resistivities for flux cutting ({rho}{sub c}) and flux flow ({rho}{sub f}) and their ratio r = {rho}{sub c}/{rho}{sub f}.
- Research Organization:
- Ames Laboratory (AMES), Ames, IA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC02-07CH11358
- OSTI ID:
- 1025252
- Report Number(s):
- IS-J 7601
- Journal Information:
- Superconductor Science and Technology, Journal Name: Superconductor Science and Technology Journal Issue: 6 Vol. 24; ISSN 0953-2048
- Country of Publication:
- United States
- Language:
- English
Similar Records
Theory of the double critical state in type-II superconductors
Theory of flux cutting and flux transport at the critical current of a type-II superconducting cylindrical wire