Ultrafast perturbation of magnetic domains by optical pumping in a ferromagnetic multilayer

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].…”

“…In these works, the manipulation of symmetry occurred within the magnetic or spin degree of freedom. However, ultrafast excitation of metallic magnetic materials [10] also induces non-equilibrium spin currents [11] that can produce torques [12] and affect the picosecond dynamics of the spin degree of freedom [13][14][15][16][17][18][19][20].…”

“…To study the far-from-equilibrium dynamics of these spatial symmetries occurring at nanoscale, time-resolved X-ray scattering from free electron lasers remains the pre- ferred method to achieve the necessary combined temporal and spatial resolution [7,11,16,17,19,20,22]. The detected scattered intensity pattern directly correlates to the domain pattern symmetry.…”

“…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.…”