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Ultrafast Demagnetization Dynamics in Room-Temperature vdW Ferromagnet Fe3GaTe2
Anji Yi1, Ding Peng1, Xia Wang2
1Wuhan National High Magnetic Field Center and Department of Physics, Huazhong University of Science and Technology, Wuhan 430074, China.
The Journal of Physical Chemistry Letters
|June 3, 2026
Summary
Ultrafast demagnetization in 2D van der Waals ferromagnets was studied using femtosecond lasers. Spin relaxation times show unique temperature dependence near the Curie temperature, offering insights into spin dynamics.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Ultrafast Phenomena
Background:
- Two-dimensional van der Waals (vdW) ferromagnets are promising for spintronics.
- Understanding ultrafast spin dynamics near the Curie temperature (TC) is crucial for device applications.
- Femtosecond laser-induced demagnetization provides a window into spin relaxation mechanisms.
Purpose of the Study:
- To investigate ultrafast spin dynamics in exfoliated Fe3GaTe2, a room-temperature vdW ferromagnet.
- To determine the spin relaxation time and its dependence on temperature and pump fluence.
- To elucidate the underlying spin relaxation mechanisms in 2D metallic magnets.
Main Methods:
- Time-resolved magneto-optical Kerr effect spectroscopy was employed.
- Femtosecond laser pulses were used to induce ultrafast demagnetization.
- A microscopic three-temperature model was utilized for quantitative analysis.
Main Results:
- A two-step demagnetization process occurring within ~100 ps was observed.
- Spin-relaxation time (τ) increased with pump fluence but showed nonmonotonic temperature dependence, peaking near TC.
- The observed Type-II behavior was linked to low spin-flip probability and proximity to TC.
Conclusions:
- The study provides quantitative benchmarks for Elliott-Yafet spin relaxation in 2D metallic magnets.
- Femtosecond laser-induced demagnetization is a viable method for probing spin dynamics in vdW ferromagnets.
- Findings contribute to the fundamental understanding of spin relaxation in novel magnetic materials.
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