Dresden 2011 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 38: Poster Session Transport

TT 38.2: Poster

Mittwoch, 16. März 2011, 14:00–18:00, P3

Magnetostrictive effects in ferromagnetic Dy break-junctions — •Marc Müller¹, Christoph Sürgers¹, Richard Montbrun¹, and Hilbert v. Löhneysen^1,2 — ¹Karlsruher Institut für Technologie, Physikalisches Institut, 76131 Karlsruhe — ²Karlsruher Institut für Technologie, Institut für Festkörperphysik, 76021 Karlsruhe

A characteristic property of the rare-earth metals are their large magnetostrictive strains which are related to the magnetocrystalline anisotropy through the elastic energy. We have investigated the electrical conductance G of mechanical break-junctions of a dysprosium wire at 4.2 K where Dy is in the ferromagnetic state. In zero magnetic field we find the usual variation of the conductance G vs. electrode distance x while breaking the wire mechanically, with a sequence of steps and more or less prominent plateaus. The behavior G(x) is modified in magnetic fields µ₀ H up to 1 T due to the large magnetostriction of Dy. In addition, the conductance can be changed reproducibly by variation of H. For a number of contacts we observe discrete changes in G(H) in the range of several G₀ = 2 e²/h. The behavior of G(H) and its angular dependence can be quantitatively understood by taking into account the magnetostrictive properties of Dy. This first realization of a magnetostrictive atomic switch demonstrates the possibility of reproducibly tuning the conductance of magnetic nanocontacts by a magnetic field.

Work supported by the DFG Center for Functional Nanostructures (CFN).