Regensburg 2007 – scientific programme

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MA: Fachverband Magnetismus

MA 12: Spindependent Transport I

MA 12.11: Talk

Tuesday, March 27, 2007, 12:45–13:00, H22

Magneto-transport hysteresis loop of a single nanostructure — •Guillemin Rodary, Sebastian Wedekind, Dirk Sander, and Jürgen Kirschner — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120, Halle (Saale), Germany

We have studied morphological, electronic and magnetic properties of a single cobalt nano-island by means of spin-dependent scanning tunneling microscopy (SP-STM) at 7K and under a high magnetic field (7T). Two monolayer high triangular Co islands are grown on Cu(111) surface at room temperature and are then imaged by STM at low temperature. Scanning tunneling spectroscopy reveals spin polarized states of the nano-islands [1]. In contrast to previous studies using the field variation of images contrast to obtain a magnetic hysteresis loop [2], we directly record the apparent topology change with magnetic field variation at a single point. This method allows to understand the magnetic properties of a single nano-object, as the coercitive field or the switching behavior. The magneto-transport hysteresis curve obtained is explained from a tunnel magnetoresitance standpoint. We discuss the precise method to obtain such measurement with a STM in comparison to solid state spin electronic experiments, specially artifacts that have been isolated.

[1] L. Diekhöner, M. A. Schneider, A. N. Baranov, V. S. Stepanyuk, P. Bruno and K. Kern, Phys. Rev. Lett. 90, 236801 (2003).

[2] O. Pietzsch, A. Kubetzka, M. Bode and R. Wiesendanger, Science 292, 2053 (2001).