Regensburg 2022 – scientific programme

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MA: Fachverband Magnetismus

MA 9: INNOMAG e.V. Prizes 2022 (Diplom-/Master and Ph.D. Thesis)

MA 9.4: Talk

Monday, September 5, 2022, 16:05–16:30, H43

High-contrast mapping of atomic-scale spin-textures — •Lucas Schneider, Philip Beck, Jens Wiebe, and Roland Wiesendanger — Department of Physics, University of Hamburg, D-20355 Hamburg, Germany

A scanning tunneling microscope (STM) with a magnetic tip that has a sufficiently strong spin polarization can be used to map the sample’s spin structure down to the atomic scale [1] but usually lacks the possibility to absolutely determine the value of the sample’s spin polarization. Magnetic impurities in superconducting materials give rise to pairs of perfectly, i.e., 100%, spin-polarized subgap resonances. In this talk, I will present a method exploiting this effect by functionalizing the apex of a superconducting Nb STM tip with such impurity states [2]. These tips can be used to probe the spin polarization of atom-manipulated Mn nanomagnets on a Nb(110) surface. By comparison with spin-polarized STM measurements of the same nanomagnets using conventional Cr bulk tips, we demonstrate an extraordinary spin sensitivity and the possibility to measure the sample’s spin-polarization values close to the Fermi level quantitatively with the new functionalized probes.

[1] R. Wiesendanger, Rev. Mod. Phys. 81, 1495 (2009)

[2] L. Schneider et al., Sci. Adv. 7, eabd7302 (2021)