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Updated: Sep 8, 2025
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Optimized Setup and Protocol for Magnetic Domain Imaging with In Situ Hysteresis Measurement
Published on: November 7, 2017
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Transient domain boundary drives ultrafast magnetisation reversal
Martin Hennecke1, Daniel Schick2, Themistoklis P H Sidiropoulos3
1Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Berlin, Germany. hennecke@mbi-berlin.de.
Nature Communications
|September 5, 2025
Summary
Ultrafast all-optical helicity-independent magnetisation switching (AO-HIS) is not just local but also a depth-dependent process. A mobile boundary within the magnetic layer dictates the switching speed and final state.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Ultrafast Phenomena
Background:
- All-optical helicity-independent magnetisation switching (AO-HIS) is a promising ultrafast phenomenon for technological applications.
- Current understanding attributes AO-HIS to local, thermally-driven angular momentum transfer.
- This local picture has been the focus of experimental and theoretical investigations.
Purpose of the Study:
- To challenge the purely local model of AO-HIS.
- To investigate AO-HIS as a spatially inhomogeneous process within thin magnetic films.
- To understand the role of transient nanoscale inhomogeneities in ultrafast switching.
Main Methods:
- Investigated a 9.4 nm thin Gd25Co75 alloy.
- Utilized techniques to probe magnetisation switching dynamics.
- Analyzed the spatial inhomogeneity of the switching process along the film depth.
Main Results:
- Demonstrated that AO-HIS is a spatially inhomogeneous process along the depth of the magnetic layer.
- Observed two distinct regions with opposite magnetisation directions separated by a mobile boundary.
- Showed that the dynamics of this transient boundary govern the final magnetisation state and switching speed.
Conclusions:
- The local picture of AO-HIS is insufficient; depth-dependent inhomogeneity is crucial.
- Transient nanoscale inhomogeneities significantly influence ultrafast switching phenomena.
- Understanding these inhomogeneities opens new avenues for designing materials and excitation scenarios for information storage and transfer devices.
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