Abstract
We investigate the static and ultrafast magneto-optical response of the hexagonal chiral helimagnet Cr1/3NbS2 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, NbS2, and Cr-intercalated compounds. Time-resolved magneto-optical Kerr effect measurements show a two-step demagnetization process, where an initial, subpicosecond relaxation and subsequent buildup (τ>50ps) 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 Cr1/3NbS2, 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 Cr1/3NbS2 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.
Original language | English |
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Article number | 174426 |
Journal | Physical Review B |
Volume | 104 |
Issue number | 17 |
DOIs | |
State | Published - Nov 1 2021 |
Funding
This work was supported by the National Science Foundation, Division of Material Research, Grant No. DMR-1151687. N.S. would like to thank Ra'anan I. Tobey for the helpful discussions. N.S. acknowledges the support of the U.S. Department of Energy through the LANL LDRD Program and the Center for Integrated Nanotechnologies at Los Alamos National Laboratory (LANL), a U.S. Department of Energy, Office of Basic Energy Science user facility. Work at Oak Ridge National Laboratory (ORNL) was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. D.M. acknowledges support from the Gordon and Betty Moore Foundation's EPiQS Initiative, Grant No. GBMF9069.