Regensburg 2013 – wissenschaftliches Programm

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MI: Fachverband Mikrosonden

MI 9: Poster: Microanalysis and Microscopy

MI 9.8: Poster

Mittwoch, 13. März 2013, 15:00–17:00, Poster B2

Optimization of the differential conductance contrast in spin-polarized room-temperature scanning tunneling microscopy of e-fct Mn on Co/Cu(001) — •Jiaming Song, Chii-Bin Wu, and Wolfgang Kuch — Freie Universität Berlin, Fachbereich Physik, Institut für Experimentalphysik, Arnimallee 14, 14195 Berlin, Germany

Spin-polarized scanning tunneling microscopy is an effective technique to study the magnetic structure of magnetic surfaces at the nanoscale. We have used a ferromagnetic Fe-ring probe with in-plane spin sensitivity to record differential conductance maps from ultra-thin epitaxial antiferromagnetic Mn layers on Co/Cu(001) at room temperature. We observe a clear contrast between areas of different Mn thicknesses, which reverses as a function of bias voltage. To compare to dI/dV-V curves of the respective areas obtained at a certain bias voltage and constant tip height, one needs to take into account the effect of different bias voltages on the tip height in areas with different spectroscopic contrast. Correcting the dI/dV-V curves correspondingly using a simultaneously recorded I-V curve leads to a good agreement with the bias dependence of the contrast that is observed in constant-current scans of differential conductance maps. This can be used to quickly estimate the bias voltages at which a contrast reversal occurs, and to identify the conditions for maximum spectroscopic spin contrast. We demonstrate this for 4.6 monolayers (ML) antiferromagnetic e-fct Mn on 4.8 ML Co/Cu(001).