Probing ultrafast magnetization dynamics via synthetic axion fields

TL;DR

This paper introduces a method to probe ultrafast magnetization dynamics by generating an effective dynamic axion field through high-frequency oscillations, enabling mapping with lower frequency signals.

Contribution

It demonstrates that high-frequency uniform magnetization oscillations can create a dynamic axion field, facilitating ultrafast magnetic measurements with simpler probe signals.

Findings

High-frequency magnetization oscillations produce an effective axion field.

The method allows mapping of ultrafast magnetization dynamics.

Potential applications in advanced magnetic sensing and metamaterials.

Abstract

Spatial structuring of materials at subwavelength scales underlies the concept of metamaterials possessing exotic properties beyond those of the constituent media. Temporal modulation of material parameters enables further functionalities. Here, we show that high-frequency oscillations of spatially uniform magnetization generate an effective dynamic axion field embedding the amplitude and phase of magnetization oscillations. This allows one to map ultrafast magnetization dynamics using a probe signal with much lower frequency.