Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 91: [MA] Poster II

O 91.47: Poster

Freitag, 30. März 2012, 11:00–14:00, Poster A

Switching the magnetization of nanomagnets using SP-STM — •Benjamin Ehlers, Gabriela Herzog, Johannes Friedlein, Stefan Krause, and Roland Wiesendanger — University of Hamburg, Institute of Applied Physics, Jungiusstraße 11A, 20355 Hamburg, Germany

With spin-polarized scanning tunneling microscopy (SP-STM) it is possible to manipulate the switching behavior of atomic-scale superparamagnets, using a high spin current generated between a magnetic tip and a magnetic sample. [1]

Here, current-induced magnetization switching of thermally quasistable magnetic nanoislands with a state lifetime on the order of several hours is demonstrated using SP-STM. The magnetization of an individual Fe nanoisland consisting of about 40 atoms on a W(110) surface is reversibly switched between two states by the application of short spin-polarized tunnel current pulses in the µA regime [2]. The combined action of Joule heating and spin-transfer torque during the pulse leads to a controlled reversal of the magnetization. The switching efficiency is evaluated as a function of different current pulse parameters, i.e. pulse length and amplitude, bias polarity and bias value.

[1] S. Krause, L. Berbil-Bautista, G. Herzog, M. Bode, and R. Wiesendanger, Science 317, 1537 (2007).

[2] G. Herzog, S. Krause, and R. Wiesendanger, Appl. Phys. Lett. 96, 102505 (2010).