Mean versus strongest signals for self-organized criticality in magnetic quantum dot arrays

Magnetodynamics of an array of ferromagnetically coupled quantum dots is considered by employing the randomly jumping interacting moments model which includes quantum fluctuations due to the dot discrete level structure, inter-dot coupling and disorder. The relevant magnetic state equation is found to indicate an existence of spinodal regions and critical points when magnetic noise signals display some universal scaling properties. On the basis of the mean-field analysis we suggest and test model-independent analytical tools in order to specify, quantify and analyze the system with respect to the observed self-organized criticality. (c) 2006 Elsevier B.V. All rights reserved.