Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 27: Bio- and Molecular Magnetism

MA 27.10: Vortrag

Donnerstag, 28. Februar 2008, 16:45–17:00, EB 202

Enhanced magnetocaloric effect in frustrated magnetic molecules with icosahedral symmetry — •Jürgen Schnack¹ and Johannes Richter² — ¹Universität Bielefeld, Fakultät für Physik, PF 100131, D-33501 Bielefeld — ²Universität Magdeburg, Institut für Theoretische Physik, PF 4120, D-39016 Magdeburg

We investigate the magnetocaloric properties of certain antiferromagnetic spin systems that have already been or very likely can be synthesized as magnetic molecules. It turns out that the special geometric frustration which is present in antiferromagnets that consist of corner-sharing triangles leads to an enhanced magnetocaloric effect with high cooling rates in the vicinity of the saturation field. These findings are compared with the behavior of a simple unfrustrated spin ring as well as with the properties of the icosahedron. To our surprise, also for the icosahedron large cooling rates can be achieved but due to a different kind of geometric frustration. [J. Schnack, R. Schmidt, J. Richter, Phys. Rev. B 76 (2007) 054413]