Manipulation of topological spin structures at ultrathin magnetic interfaces by oxygen adsorption and interlayer exchange coupling
Tzu-Hung Chuang1*, Liang-Wei Lan2, Ming-Ching Wu1, Chia-Chi Liu1, Yao-Jui Chan2, Chih-Heng Huang3, Chien-Cheng Kuo2, Der-Hsin Wei1,3
1Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan
2Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan
3International PhD Program for Science, National Sun Yat-sen University, Kaohsiung, Taiwan
* Presenter:Tzu-Hung Chuang,
Magnetic skyrmions have been investigated from fundamental physics to applications for next generation high-density information encoding. Such non-collinear magnetic structures at interfaces are usually attributed to the Dzyaloshinskii-Moriya interaction (DMI) when the inversion symmetry is broken.
Here we report two ultrathin ferromagnetic systems, where the first one demonstrates a microscopic insight on how the oxygen adsorption modulates the spin reorientation transition (SRT) of a Fe/Ni bilayer on Cu(100) [1] and consequently impacts on the DMI of the interface. The second case shows that even in a negligible DMI interface, such as Co/Au(111), magnetic skyrmion bubbles can be stabilized at room temperature in the metastable phase of spin canting configuration within the SRT by interlayer exchange coupling across a non-magnetic spacer layer [2]. The magnetic images are measured by X-ray magnetic circular dichroism (XMCD) based photoemission electron microscopy (PEEM), and the experimental results are discussed with the help of micromagnetic simulations.
The project is financially supported by Ministry of Science and Technology (MOST 105-2112-M-213 -012 -MY2 and MOST 107-2112-M-213-008) and National Synchrotron Radiation Research Center.

[1] T.-H. Chuang, et al., Microscopy and Microanalysis 24 (S2), 550 (2018).
[2] T.-H. Chuang, et al., (in preparation)

Keywords: XPEEM, XMCD, Dzyaloshinskii-Moriya interaction, skyrmions