physica status solidi (a)

Cover image for Vol. 213 Issue 12

Editor: Stefan Hildebrandt (Editor-in-Chief), Sabine Bahrs (Deputy Editor)

Online ISSN: 1862-6319

Associated Title(s): physica status solidi (b), physica status solidi (c), physica status solidi (RRL) - Rapid Research Letters

208_11b/2011Back Cover: Numerical analysis of superparamagnetic clusters distribution (Phys. Status Solidi A 11/2011)

Modern magnetic materials containing nanosized objects can exhibit superparamagnetic behaviour. From the measured magnetic isotherms one can calculate a distribution of the magnetic moment of superparamagnetic clusters which is the main goal of the so-called Langevin granulometry. The cover image presents a result of such analysis obtained by making use of different calculation procedures developed in the article by Chrobak et al. (pp. 2692-2698). The problem is how to determine the cluster distribution consisting of several hundreds of channels based on a magnetic isotherm with only a few dozen points. The apparent lack of information can be supplemented by a physical model as well as a proper calculation procedure. The so-called simulated annealing procedure with additional local maximum entropy condition gives physical reliable results. The image shows the efficiency of the tested algorithms which were applied to the reconstruction of a known cluster distribution. In the background the used algorithm in Pascal style pseudocode is displayed.

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