Ultrafast time-evolution of chiral Néel magnetic domain walls probed by circular dichroism in x-ray resonant magnetic scattering

Symmetry-dependent ultrafast manipulation of nanoscale magnetic domains

“…3d. These observations are consistent with previous works where a shift in the radial wavevector q was only observed when measuring isotropic scattering from labyrinth domains [16,20,24] and no shift reported for anisotropic scattering from stripe domains [17,19]. We note that the detected shifts (1-4 %) are smaller than those observed in earlier works (5-6 %) [16,20].…”

“…Later studies in CoFe/Ni multilayers that could access higher order diffraction rings were able to disentangle domain-wall broadening from the periodicity, suggesting an ultrafast domain rearrangement [20]. More recently, a similar shift in the scattered ring was observed for chiral labyrinth domains [23,24]. This shift, however, has not been observed in stripe domains [17,19,25], apparently contradicting earlier works.…”

“…Traditionally, the time-dependent 2D scattering has been analyzed within a 1D representation achieved by azimuthal integration, either over the isotropic ring [16,20,23,24] or the anisotropic lobes [17,19]. However, our scattering data precludes this simple analysis, both because of the mixed isotropic-anisotropic scattering and because of the significant amount of data lost to the nonactive regions of the detector.…”

Chiral spin spiral in synthetic antiferromagnets probed by circular dichroism in x-ray resonant magnetic scattering

“…Only advanced MFM in vacuum or NV magnetometry permit clear imaging of such magnetic texture [15,17]. The need for a technique allowing to probe chiral stability, 3D textures [18] or the ultrafast dynamics [19,20] of these magnetic textures is particularly crucial in the context of SAFs. Recently, we showed that the amplitude and sign of the circular dichroism in x-ray resonant magnetic scattering (XRMS) can determine the effective chirality, i.e., its type (Néel or Bloch) and its magnetic chirality in ferromagnetic multilayers (FM) [21,22].…”

“…Based on the results of the micromagnetic simulations, we now simulate the expected specular reflectivities and XRMS patterns and compare them with the experiments. While we have already simulated XRMS for FM multilayers assuming that all the magnetic layers have the same magnetization and considering only one layer [20,21], this is not a valid hypothesis in the case of AFM coupled multilayers. As a consequence, two layers have to be considered for the magnetic unit cell.…”