Picosecond-scale coherent toggle switching of topological spin helicity

Area of Science:

• Spintronics
• Condensed Matter Physics
• Materials Science

Background:

• Conventional magnetization switching is key for spintronics, but controlling topological spin configurations like magnetic vortices is difficult.
• Maintaining the topology during spin precession is crucial for applications in multistate memory and neuromorphic computing.

Purpose of the Study:

• To experimentally demonstrate coherent helicity toggle switching in nanoscale magnetic vortices.
• To investigate the mechanism behind this switching and explore methods for controlling it.

Main Methods:

• Utilizing femtosecond laser pulse excitation under an out-of-plane magnetic field.
• Observing switching dynamics on picosecond timescales.
• Employing micromagnetic simulations for validation and parameter optimization.

Main Results:

• Achieved coherent helicity switching in magnetic vortices within hundreds of picoseconds.
• Identified ultrafast photothermal demagnetization and coherent spin precession as the governing mechanism.
• Demonstrated precise tunability of switching dynamics (deterministic to stochastic) via laser fluence and magnetic field.

Conclusions:

• The study presents a viable method for coherent helicity switching in magnetic vortices, preserving their topology.
• This technique allows for fine-tuned control over spin states, paving the way for advanced spintronic devices.
• The findings are reproducible and validated through micromagnetic simulations.