Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 63: Posters: Scanning Probe Methods

O 63.8: Poster

Mittwoch, 2. April 2014, 17:30–21:00, P2

Capacitively guided tip-to-tip positioning for multiprobe spin-polarized scanning tunneling microscopy — •Jonas Harm, Johannes Friedlein, Andreas Sonntag, Stefan Krause, and Roland Wiesendanger — Institute of Applied Physics, University of Hamburg, Hamburg, Germany

To investigate magnetic transport properties on the atomic scale, we currently set up a multiprobe spin-polarized scanning tunneling microscope (SP-STM), that is designed for high-frequency applications in a magnetic field of 3 T at temperatures below 2 K in ultra-high vacuum. One of the challenges in such a system is the positioning of two tunneling tips at a distance of only a few nanometers. The external magnetic field excludes the use of a scanning electron microscope for positioning the tips within a common scan frame [1]. We present a novel tip-to-tip approach, extending known tip-to-tip tunneling methods [2,3] by utilizing distance dependence of the capacitance between two tips, allowing a fast and safe approach. Since the minimum distance between the tips is limited by their tip radii and opening angles, we adapted tip preparation techniques [4], thereby enabling future transport measurements at tip-to-tip distances in the range of 10−20 nm.
 
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