Dresden 2014 – scientific programme
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MA: Fachverband Magnetismus
MA 53: Spin Structures at Surfaces and in thin films II
MA 53.8: Talk
Friday, April 4, 2014, 11:15–11:30, BEY 118
Superconducting scanning tunneling microscope tips as probes for absolute spin-polarization — •Matthias Eltschka1, Berthold Jäck1, Maximilian Assig1, Markus Etzkorn1, Christian R. Ast1, and Klaus Kern1, 2 — 1Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany — 2Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
Spin-polarized tunneling pioneered by Robert Meservey and Paul Tedrow has become an essential field of study and opened up the way for many applications [1]. We transfer the concept of superconducting detector electrodes commonly used in standard thin film sandwich junctions to scanning tunneling microscopy (STM) to locally probe absolute spin-polarization. We have studied superconducting vanadium STM tips on normal conducting samples in high magnetic fields at 10 mK. The superconducting properties of those tips are determined by the confinement due to the specific tip geometry. Superconducting STM tips have been employed as local probe for the absolute spin-polarization of Co nanoislands on Cu(111). Our results qualitatively agree with experiments carried out by SP-STM [2] but the absolute values of the measured spin-polarization allows for further analysis of the orbital wave functions involved in the tunneling process.
[1] P. M. Tedrow et al., Phys. Rev. Lett. 25, 1270 (1970); P. M. Tedrow and R. Meservey, Phys. Rev. Lett. 26, 192 (1971). [2] H. Oka et al., Science 327, 843 (2010).