Self-organized criticality in the Bean state in 7-x thin filmsC. M. Aegerter, M. S. Welling and R. J. Wijngaarden
Division of Physics and Astronomy, Vrije Universiteit De Boelelaan 1081, 1081HV Amsterdam, The Netherlands
(Received 4 August 2003; accepted in final form 22 January 2004)
The penetration of magnetic flux into a thin film of 7-x is studied when the external field is ramped slowly. In this case, the flux penetrates in bursts or avalanches. The size of these avalanches is distributed according to a power law with an exponent of . The additional observation of finite-size scaling of the avalanche distributions, with an avalanche dimension D = 1.89(3), gives strong indications towards self-organized criticality in this system. Furthermore, we determine exponents governing the roughening dynamics of the flux surface using some universal scaling relations. These exponents are compared to those obtained from a standard roughening analysis.
05.65.+b - Self-organized systems.
45.70.Vn - Granular models of complex systems; traffic flow.
74.25.Qt - Vortex lattices, flux pinning, flux creep.
© EDP Sciences 2004