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AM: Magnetismus

AM 3: Magnetowiderstand I

AM 3.11: Vortrag

Montag, 26. März 2001, 17:00–17:15, S 5.2

Nonequilibrium transport through ferromagnetic nanoparticles — •Silvia Kleff¹, Jan von Delft¹, M. Deshmukh², S. Gueron², E. Bonet², and D.C. Ralph² — ¹Institut fuer Theoretische Festkörperphysik, Universität Karlsruhe — ²Laboratory of Atomic and Solid State Physics,Cornell University

We propose a simple toy model for an ultrasmall ferromagnetic grain, formulated in terms of the grain’s discrete energy levels. We delineate which many-body electron states one must consider in analyzing the measurements by Deshmukh et al. and Guron et al. [1] of the discrete tunneling spectrum through such a grain. The matrix elements determining the strength of some tunneling transitions are greatly enhanced over others on account of magnetic correlations. We explore the consequences of mesoscopic fluctations in magnetic anisotropy between different eigenstates, and of nonequilibrium effects such as spin accumulation, both of which are central for an interpretation of the data.

[1] Gueron et al., Phys. Rev. Lett. 83, 4148 (1999).