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Strong ultrafast demagnetization due to the intraband transitions
1Department of Physics, Indiana State University, Terre Haute, IN 47809, United States of America.
Journal of Physics. Condensed Matter : an Institute of Physics Journal
|September 4, 2023
Summary
Ultrafast laser pulses cause demagnetization in ferromagnetic materials. A new method incorporating intraband transitions dramatically enhances demagnetization, aligning with experimental observations in spintronic materials.
Area of Science:
- Solid State Physics
- Materials Science
- Quantum Mechanics
Background:
- Femtosecond laser-induced demagnetization in ferromagnetic materials is crucial for spintronics.
- Previous *ab initio* calculations using the velocity gauge failed to replicate experimental demagnetization levels.
Purpose of the Study:
- To develop a new theoretical method for calculating ultrafast demagnetization.
- To accurately model the role of intraband transitions in laser-driven demagnetization.
Main Methods:
- Proposed a method incorporating intraband transitions via a convective derivative in crystal momentum space.
- Utilized the time-dependent quantum Liouville equation for calculations.
- Investigated bulk crystals of iron (Fe), cobalt (Co), and nickel (Ni).
Main Results:
- Inclusion of intraband transitions significantly enhanced demagnetization, matching experimental data.
- The impact of intraband transitions varied distinctly among Fe, Co, and Ni due to their unique band structures and spin properties.
Conclusions:
- The developed method accurately captures ultrafast demagnetization phenomena.
- Intraband transitions play a critical, material-dependent role in laser-induced demagnetization.
- Findings advance the understanding of ultrafast demagnetization for spintronic device development.
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