Berlin 2012 – wissenschaftliches Programm
MA 37.13: Vortrag
Donnerstag, 29. März 2012, 12:45–13:00, EB 301
Spin transfer torque and Joule heating of field-emitted electrons — •Anika Schlenhoff, Andreas Sonntag, Stefan Krause, and Roland Wiesendanger — Institute of Applied Physics, University of Hamburg
Since the detection of the spin polarization of field-emitted electrons in the 1970’s , it is an open question which type of effects a high spin-polarized current of field-emitted electrons has onto a magnetic sample. Though spin-polarized two-photon photoemission has gained first insight into the interaction of hot electrons with an underlying spin system , the microscopic details still remain to be discovered.
In our studies, we utilize spin-polarized scanning tunneling microscopy (SP-STM) in the field emission mode  for the direct observation of the influence of field-emitted electrons onto atomic-scale superparamagnets . The experiments reveal that the injection of high spin-polarized currents via the first field emission resonance (FER) significantly changes the superparamagnet’s switching behavior. Telegraphic noise experiments allow for a detailed current-dependent lifetime analysis, thereby quantifying the spin-transfer torque and Joule heating of the field-emitted electrons. The results are compared to low energy electrons tunneling directly into the nanoisland.
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