Quantifying exchange forces of a spin spiral on the atomic scale

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Chiral magnetic structures are crucial for advanced nanoscale magnetic storage and logic devices.
• Existing methods for quantifying atomic-scale exchange interactions, primarily current-based sensing, have limitations.
• A force-based detection scheme offers a more advantageous approach for atomic-scale magnetic interaction quantification.

Purpose of the Study:

• To develop and apply a novel method for quantifying atomic-scale exchange force fields.
• To investigate the atomic-scale exchange force field between a ferromagnetic tip and a cycloidal spin spiral.
• To compare the sensitivity of exchange force detection versus spin polarization for atomic-scale magnetic variations.

Main Methods:

• Development of a combined current and exchange force detection scheme.
• Quantification of the atomic-scale exchange force field using the developed method.
• Utilizing first-principles calculations to analyze the origins of measured exchange force variations.

Main Results:

• The exchange force field demonstrates higher sensitivity to atomic-scale magnetization variations compared to spin polarization.
• Atomic-scale variations in the exchange force field were successfully quantified.
• First-principles calculations identified direct and indirect (Zener-type) exchange mechanisms as sources of these variations, dependent on tip termination.

Conclusions:

• The developed force-based detection scheme provides a powerful tool for probing atomic-scale magnetic interactions.
• Exchange force field measurements offer superior sensitivity to magnetization details over spin polarization.
• This work enables precise quantification of diverse exchange mechanisms in chiral magnetic structures via 3D magnetic exchange force field mapping.