Europhys. Lett.
Volume 65, Number 6, March 2004
Page(s) 753 - 759
Section General
Published online 01 March 2004
Europhys. Lett., 65 (6) , pp. 753-759 (2004)
DOI: 10.1209/epl/i2003-10132-1

Self-organized criticality in the Bean state in $\chem{YBa_2Cu_3O}$ 7-x thin films

C. 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 $\chem{YBa_2Cu_3O}$ 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 $\tau = 1.29(2)$. 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