Ultrafast magnetization and structural dynamics in the intercalated transition metal dichalcogenides Fe0.25TaS2 and Mn0.25TaS2

We measure magnetization and structural dynamics in two intercalant-ordered transition metal dichalcogenides: Fe0.25TaS2 and Mn0.25TaS2. The structurally equivalent materials allow us to probe the effect of orbital angular momentum which is active in Fe0.25TaS2 and absent in Mn0.25TaS2. Interestingly, we find that the magnetooptics dynamics are nearly indistinguishable in these two materials, in contradiction to conventional explanations of a spin-lattice mechanism. We compare our results to other materials where spin-lattice demagnetization has been put forth as a demagnetization channel.