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Universal Criteria for Single Femtosecond Pulse Ultrafast Magnetization Switching in Ferrimagnets
1Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany.
Physical Review Letters
|July 29, 2022
Summary
This study presents a new theory for understanding magnetization switching in ferrimagnetic materials using femtosecond lasers. The macroscopic theory accurately models the switching process and provides universal criteria for ferrimagnet switching.
Area of Science:
- Physics
- Materials Science
- Magnetism
Background:
- Single-pulse switching in ferrimagnetic materials like GdFeCo and Mn2RuGa has been observed experimentally.
- A complete theoretical understanding of the nonequilibrium reversal path induced by femtosecond laser photoexcitation is lacking.
Purpose of the Study:
- To develop a general macroscopic theory for magnetization dynamics in ferrimagnetic materials under femtosecond laser excitation.
- To quantitatively reproduce experimental switching processes and provide a theoretical framework for understanding the underlying physics.
Main Methods:
- Development of a general macroscopic theory for magnetization dynamics.
- Comparison of the theory with atomistic spin dynamics simulations.
- Analysis of magnetization relaxation rates and microscopic parameters.
Main Results:
- The proposed theory quantitatively reproduces all stages of the single-pulse switching process observed in experiments.
- Direct comparison with simulations for GdFeCo and Mn2RuGa alloys validates the theory.
- Explicit expressions for magnetization relaxation rates are derived.
Conclusions:
- The developed macroscopic theory provides a comprehensive understanding of femtosecond laser-induced switching in ferrimagnets.
- The derived expressions and criteria facilitate the prediction and optimization of switching in magnetic materials.
- This work bridges the gap between experimental observations and theoretical understanding of ultrafast magnetic phenomena.
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