Symmetry-dependent ultrafast manipulation of nanoscale magnetic domains

The quest towards controlling magnetism at the femtosecond timescales is driven by the demand for energy efficient and fast magnetic storage devices¹. Many studies have focused on switching the magnetization in different material, but few have discussed the role of the spatial evolution of the magnetization.

Here, we study the ultrafast response of magnetic multilayers with domain patterns with different local symmetries. Through time-resolved small angle X-ray scattering at the European XFEL and an accurate 2D fitting routing, we find a symmetry-dependent behavior of the ultrafast response. By observing an ultrafast shift in the scattering peak position for labyrinth domains, without translational symmetry, but no such shift for stripe domains, with translational symmetry, we confirm the results of previous studies². We also study regions of the sample where both labyrinth and stripe characters are present. By isolating the isotropic and anisotropic components of the scattering, we find that only the labyrinth domains exhibit an ultrafast shift in the isotropic diffraction peak position, even in a mixed domain pattern. Our findings reveal the unpredicted dependence of the ultrafast spin dynamics on the configuration of the magnetic domains and invites further investigation on far-from-equilibrium spin transport.

¹Kirilyuk, Kimel, Rasing, RevModPhys 82 (2010)

²Pfau et al., Nat Comm 3 (2012); Vodungbo et al., Nat Comm 3 (2012), Zusin et al, accepted PRB (2022); Hennes et al., PRB 102 (2020)