Fabian Kammerbauer1, Won-Young Choi1, Frank Freimuth2, Kyujoon Lee3, Robert Frömter1, Dong-Soo Han4, Yuriy Mokrousov1,2, and Mathias Kläui1
1 Institute of Physics, Johannes Gutenberg University, Staudingerweg 7, 55128 Mainz, Germany
2 Center for Spintronics, Korea Institute of Science and Technology, Hwarang-ro 14 gil 5, Seoul, Republic of Korea
3 Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
4 Division of display and semiconductor physics, Korea University, Sejong-ro 2511, Sejong, Republic of Korea
The exchange interaction comes in two flavours – the symmetric and antisymmetric part. The symmetric term (typically Heisenberg Exchange) governs the ferro- and antiferromagnetism while the antisymmetric term, typically called DzyaloshinskiiMoriya interaction (DMI), promotes topologically non-trivial chiral spin textures that promise new magnetic devices.
Layered synthetic antiferromagnets can display in addition to the typical symmetric interlayer RKKY interaction also an antisymmetric interlayer DMI due to symmetry breaking within the sample plane [1, 2]. This effect favours noncollinear alignment between adjacent layers and thus provides an additional handle to engineer magnetic structures and could enable three-dimensional topological structures. It has already been reported that electrical currents can be used to tune the strength of the interface DMI, [3]. Here, we report the effect of an electrical current on the antisymmetric interlayer DMI by employing anomalous Hall effect measurements with an additional applied in-plane field. In order to quantify the current dependence of the antisymmetric interlayer exchange interaction, an interlayer DMI field is introduced. Using a model of two superimposed cosine functions accounting for current-dependent and static contributions, we demonstrate that the current-dependent interlayer DMI field increases linearly with current and maximal along the direction of current flow. Additionally, we show that the effect is odd in current. Thus, we demonstrate the
possibility to control the interlayer DMI directly by electrical currents, which allows for new switching mechanisms in three-dimensional magnetic textures.
References
[1] D.-S. Han, et al., Nat. Mater. 18, 703-708 (2019)
[2] A. Fernández-Pacheco, et al., Nat. Mater. 18, 679-684 (2019)
[3] G.V. Karnad, et al., Phys. Rev. Lett. 121, 147203 (2018)