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arXiv · 2605.18638

Electronic mechanism of sub-100-fs demagnetization induced by a femtosecond light pulse

Konrad J. Kapcia·Victor Tkachenko·Flavio Capotondi·Alexander Lichtenstein·Serguei Molodtsov·Przemysław Piekarz·Beata Ziaja
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Abstract

A quantitative understanding of the processes that trigger light-induced demagnetization on ultrashort timescales is crucial for achieving an ultrafast, radiation-controlled magnetic response in materials. This milestone is essential for developing next-generation magnetic storage devices and ultrafast magnetic switches. In this theoretical study, we investigated demagnetization triggered in a single magnetic domain by light pulses ranging from a few to a few tens of femtoseconds in duration, with photon energies spanning the optical and X-ray regimes, under strongly non-equilibrium conditions. We predicted a loss of magnetization in the sub-100-fs range in all cases, primarily due to the excitation of the electronic system and the subsequent redistribution of electrons within the magneto-sensitive band. The considered timescales were too short for phonon-mediated processes or inter-site Heisenberg exchange processes to contribute significantly. These findings pave the way for highly accurate, radiation-driven magnetization control in magnetic materials at sub-100-femtosecond timescales with potential practical applications.

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Konrad J. Kapcia, Victor Tkachenko, Flavio Capotondi, Alexander Lichtenstein, Serguei Molodtsov, Przemysław Piekarz, Beata Ziaja. 2026-05-18. Electronic mechanism of sub-100-fs demagnetization induced by a femtosecond light pulse. https://doi.org/10.1038/s41598-026-51949-2

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