Nanocluster Ensembles: Preparation, Characterization and Fundamental Thermodynamic Properties

Jody Redepenning, Christian Binek, and Nathanael Fackler

The seed project uses a chemical route to fabricate self assembled monolayers and multilayers of magnetic nanoparticles with tailored particle spacing. The preparation is based on the thermal decomposition of metal carbonyls in the presence of appropriate surfactants. Structural and magnetic characterization involves TEM, SQUID, alternating gradient force and Kerr magnetometry as well as susceptometry. The systematic variation of the particle spacing allows on the one hand exploring the interaction regime of collective ferromagnetic, antiferromagnetic or spin-glass like behavior and studying corresponding interaction mechanisms like tunneling mediated exchange for instance.
On the other hand, pure dipolar interaction is achieved in the limit of large particle spacing. Here we aim on scaling properties which evidence the transition from extensive thermodynamics in 2d to non-extensive thermodynamics in 3d dipolar systems.

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