Disentangling Electronic, Lattice and Spin Dynamics in the Chiral Helimagnet Cr1/3NbS2

Abstract

We investigate the static and ultrafast magneto-optical response of the hexagonal chiral helimagnet $C{r}_{1/3}Nb{S}_2$ above and below the helimagnetic ordering temperature. The presence of a magnetic easy plane contained within the crystallographic ab-plane is confirmed, while degenerate optical pump-probe experiments reveal significant differences in the dynamic between the parent, $Nb{S}_2$, and Cr-intercalated compounds. Time resolved magneto-optical Kerr effect measurements show a two-step demagnetization process, where an initial, sub-ps relaxation and subsequent buildup ($\tau >50$ ps) in the demagnetization dynamic scale similarly with increasing pump fluence. Despite theoretical evidence for partial gapping of the minority spin channel, suggestive of possible half metallicity in $C{r}_{1/3}Nb{S}_2$, such a long demagnetization dynamic likely results from spin lattice-relaxation as opposed to minority state blocking. However, comparison of the two-step demagnetization process in $C{r}_{1/3}Nb{S}_2$ with other 3d intercalated transition metal dichalcogenides reveals a behavior that is unexpected from conventional spin-lattice relaxation, and may be attributed to the complicated interaction of local moments with itinerant electrons in this material system.

20 pages, 10 figures, 1 Table

References in corpus (6)

• Spontaneous Skyrmion Ground States in Magnetic Metals
• Super-Diffusive Spin-Transport as a Mechanism of Ultrafast Demagnetization
• Structural disorder versus chiral magnetism in Cr${}_{1/3}$NbS${}_2$
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Cited by in corpus (2)

• Comparative Electronic Structures of the Chiral Helimagnets Cr1/3NbS2 and Cr1/3TaS2
• Nonequilibrium dynamics of $\alpha$-RuCl${}_3$ -- a time-resolved magneto-optical spectroscopy study