So, if you are planning to attend the DPG spring meeting, I would be happy to see you there!
DPG spring meeting 2012 in Berlin
"Joule Heating and Spin-Transfer Torque Investigated on the Atomic Scale Using a Spin-Polarized
Scanning Tunneling Microscope".The influence of a high spin-polarized tunnel current onto the switching behavior of a superparamagnetic nanoisland on a nonmagnetic substrate is investigated by means of spin-polarized scanning tunneling microscopy. A detailed lifetime analysis allows for a quantification of the effective temperature rise of the nanoisland and the modification of the activation energy barrier for magnetization reversal, thereby using the nanoisland as a local thermometer and spin-transfer torque analyzer. Both the Joule heating and spin-transfer torque are found to scale linearly with the tunnel current. The results are compared to experiments performed on lithographically fabricated magneto-tunnel junctions, revealing a very high spin-transfer torque switching efficiency in our experiments.
S. Krause, G. Herzog, A. Schlenhoff, A. Sonntag, and R. Wiesendanger:
Phys. Rev. Lett. 107, 186601 (2011)
Press releases:
Press release of the SFB668 / University of Hamburg (in German)
News on IDW online (in German)
I am really happy to announce that I have been awarded by the "Helmholtz Center Geesthacht Dissertationspreis für verständliche Wissenschaft" prize.
Seven candidates presented their scientific work, each in a 8 minutes talk. The "dummy audience" in the "Kleine Theater Schillerstraße"
located in Geesthacht, Germany, was a mixture of all age and backgrounds, including
several school classes. It was quite a hard competition, because all contributions were really interesting, and every single candidate
was worth to be honoured by the first place. However, the jury consisting of representatives of media, science, politics and business,
had to find out the top three persons. Among with Miriam Weber from the Max Planck Institute for Marine Microbiology
in Bremen on third place and Dominik Paquet from the LMU Munich on the second place, it was me to be the winner of the contest.
I thank the jury for their decision and the Helmholtz Center Geesthacht for establishing this kind of prize :)
Press releases:
Press release of the Helmholtz Center Geesthacht (in German)
Press release of the SFB668 / University of Hamburg (in German)
News on IDW online (in German)
More information: Announcement of the Helmholtz Center Geesthacht (in German)
A full magnetic characterization of bulk Cr tips has been achieved using spin-polarized scanning tunneling microscopy at low temperature. A detailed bias-dependent study of the spatial magnetic sensitivity on the system of 1.5 monolayers of Fe/W(110) reveals that all magnetic directions in space are sensed over a wide bias range, thereby indicating a canted magnetization direction being a typical feature of bulk Cr tips. Consequently, using Cr as tip material allows any standard scanning tunneling microscope setup to be extended by the spin-polarized mode.
A. Schlenhoff, S. Krause, G. Herzog, and R. Wiesendanger:
Appl. Phys. Lett. 97, 083104 (2010)
I am proud to be honoured by the Dissertation Prize of the Prof. Dr. Jürgen Geiger Foundation.
At the Stiftskeller in Kaiserslautern, I gave a short presentation on my Ph.D. thesis.
Thanks to Dr. Jan Geiger (foundation president) and Karin Deckert (Kaiserlautern savings bank) for their speeches,
and of course many thanks to Prof. Dr. Roland Wiesendanger for the fabulous laudatio! See press article on nachrichten-kl.de (in German).
See press release on News on IDW online (in German).
Current-induced magnetization switching of thermally quasistable magnetic nanoislands is demonstrated using a spin-polarized scanning tunneling microscope. The magnetization of an individual Fe nanoisland consisting of about 40 atoms on a W(110) surface is reversibly switched between two quasistable states by the application of spin-polarized tunnel current pulses without an applied magnetic field. The pulse length is shown to be crucial for a high switching efficiency. Sweeping the tunnel current from the nanoampere to the microampere regime allows for the determination of critical switching currents.
G. Herzog, S. Krause, and R. Wiesendanger:
Appl. Phys. Lett. 96, 102505 (2010)