Thermodynamics of Finite Magnetic Two-Level Systems.

von P. Borrmann, Heinrich Stamerjohanns, E. Hilf, P. Jund, S. Kim, D. Tománek
Journal: APS March Meeting Abstracts
Pages: L3326
We use Monte Carlo simulations to investigate the thermodynamical behaviour of aggregates consisting of few superparamagnetic particles in a colloidal suspension. The potential energy surface of this classical two-level system with a stable and a metastable ``ring'' and ``chain'' configuration is tunable by an external magnetic field and temperature. We determine the complex ``phase diagram'' of this intriguing system and analyze thermodynamically the nature of the transition between the ring and the chain ``phase''.