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Manipulation of interface-induced Skyrmions studied with STM

Kirsten von Bergmann- University of Hamburg, Germany

LPS Bât 510 - grand amphi

Magnetic skyrmions are particle-like knots in the magnetization. They are envisioned as
the basis for future spintronic devices and can be stabilized by a favorable interplay of
magnetic exchange, Dzyaloshinskii-Moriya interaction (DMI), anisotropy and Zeeman
energy. The Fe/Ir(111) interface is known to exhibit strong DMI [1] and serves as an
ideal basis to build up materials that host single skyrmions on the nanometer length
scale. Such small magnetic objects can be imaged, characterized and manipulated using
(spin-resolved) scanning tunneling microscopy (STM) [2].

Building upon the Fe/Ir(111)-interface a fine-tuning of the relevant magnetic energies is
performed by adding metallic overlayers, by adorption of hydrogen, or by a variation of
the strain within the magnetic film. Magnetic field dependent STM measurements can
be used to obtain the specific material parameters [3]. In addition, spectroscopy using a
non-magnetic tip electrode reveales the correlation between the local magnetoresistance
and the non-collinearity of the spin texture [4]. Such a read-out of the local magnetic
state could be combined with the demonstated reversible switching between skyrmion
and ferromagnet by local electric fields [5].

[1] S. Heinze et al., Nature Phys. 7, 718 (2011).
[2] K. von Bergmann et al., J. Phys. : Condens. Matter 26, 394002 (2014).
[3] N. Romming et al., Phys. Rev. Lett. 114, 177203 (2015).
[4] C. Hanneken et al., Nature Nanotech. 10, 1039 (2015).
[5] P.-J. Hsu et al., Nature Nanotech. 12, 123 (2017).


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