Workshop book - Physikzentrum der RWTH Aachen - RWTH Aachen ...

Talks Monday February 4
Transport through individual magnetic molecules
Herre van der Zant, Kavli Institute of Nanoscience Delft, The Netherlands
By merging the fields of molecular magnetism, molecular electronics and
nanotechnology, we fabricate planar three-terminal nanodevices containing
individual magnetic molecules or nanoparticles. Source and drain electrodes
are made of Au or of (multi-layered) graphene. A third gate electrode allows
the modification of charge transport independently from the source/drain
electrodes. In this way, a spin transistor is built in which the electric current
through the individual magnetic molecule or nanoparticle is sensitive to its
spin properties. The molecular complexes of interest are single-molecule magnets
(SMMs) and spin-crossover compounds. Coulomb blockade is generally
observed but finer details such as Kondo correlations and excited states are
observed at cryogenic temperatures [1]. In a Fe-4 SMM based transistor, we
observe features that confirm the high-spin state and find Kondo behavior,
spin blockade and a zero-field splitting that depends on the redox state; in
the charged state the molecule turns out to be a better magnet. Using an
in-situ sample rotator, direct observation of magnetic anisotropy has been
demonstrated [3]. Recent progress includes transport through a single spincrossover
molecule [4] and the fabrication of a molecular memory device based
on a spin-crossover nanoparticle that operates near room temperature [5].
Interestingly for molecular spintronics, the spin crossover in these devices
can be induced by applying a voltage, showing that its magnetic state is
controllable electrically.
Work supported by FOM and through the EU FP7 program (ELFOS)
[1] H.B. Heersche et al., Rev. Lett. 96 (2006) 206801; E.A. Osorio et al.,
Nano Letters 10 (2010) 105; J.M. Thijssen and H.S.J. van der Zant, Phys.
stat. sol. (b) 245 (2008) 1455-1470.
[2] A. Zyazin et al. Nano Letters 10 (2010) 3307.
[3] E. Burzurí, A.S. Zyazin, A. Cornia and H.S.J. van der Zant, Phys. Rev.
Lett. 109 (2012) 147203.
[4] V. Meded et al., Phys. Rev. B 83 (2011) 245115.
[5] F. Prins et al. Adv. Mat. 23 (2011) 1545.
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