Denis Mettus
Skyrmions are topologically non-trivial spin textures that exhibit an exceptionally efficient coupling to spin currents, notably spin-polarized charge currents and magnon currents as observed in MnSi, FeGe, and Cu2OSeO3, respectively [1, 2, 3]. This raises the question for the microscopic mechanisms that control the pinning of the skyrmion lattice, and how they depend on the topology, electronic structure, and disorder.
Small angle neutron scattering has proven itself as a powerful tool for exploring the behavior of such magnetic textures in bulk materials. By utilizing the so-called Time-Involved Small-Angle Neutron scattering Experiments (TISANE), one may reach sub-millisecond time resolution and directly track the unpinning of the skyrmion lattice under periodic changes of magnetic field [4,5].
In the talk, we compare the unpinning processes in different systems, such as Mn1-xFexSi where spin-transfer torques are dominated by spin-polarized charge currents, and insulating material Cu2OSeO3 with the spin transfer torques are due to magnon currents. This provides insights into the pinning mechanisms and elasticity moduli as a precondition for the development of spintronics devices.
[2] K. Everschor et al., PRB 86, 054432 (2012)
[3] S. Zang et al., Nat. Comm. 9, 2115 (2018)
[4] S. Mühlbauer et al., New J. Phys. 18, 075017 (2016)
[5] D. Mettus et al., J. Appl. Cryst. 55, 1603-1612 (2022)