Figure 2: Demagnetization of the [Co/Pt] layer.
From: Spin current generated by thermally driven ultrafast demagnetization
(a) Demagnetization of the [Co/Pt] layer of the Cu-80 nm sample measured with the probe beam on the Pt side (black square) and that of the Cu-20 nm sample with probe beam on the Cu side (red circle). Normalizing with static Kerr rotation, the relative change in magnetization ΔM/M is −0.08±0.02 and −0.07±0.02, respectively, at 0.5 ps with the same pump fluence of 17.3 J m−2. The peak observed at 6 ps is an artefact due to coherent interference between the pump and probe light due to a stray reflection. (b) The result of thermal analysis. Pt phonon temperature from a TDTR measurement on the Pt side (black square), Cu phonon temperature from a TDTR measurement on the Cu side (red circle) and [Co/Pt] magnon temperature from MOKE measurement on the Pt side (blue triangle). Solid and dotted lines are results of thermal modelling; black solid line is for Pt phonon temperatures; red solid line is for Cu phonon temperatures; blue solid line is for [Co/Pt] phonon temperatures; blue dotted line is for [Co/Pt] electron temperatures. The thermal modelling is done by solving heat diffusion equations of Pt/[Co/Pt]/Cu structure (see Supplementary Note 4 for details about thermal modelling).
