Revealing the role of orbital magnetism in ultrafast laser-induced demagnetization in multisublattice metallic magnets by terahertz spectroscopy

TL;DR

This study uses terahertz spectroscopy to investigate ultrafast laser-induced magnetization dynamics in multisublattice metallic magnets, revealing the significant role of orbital magnetism and differing dynamics among materials.

Contribution

It demonstrates the application of simultaneous THz emission and magneto-optical measurements to understand ultrafast demagnetization, highlighting the influence of orbital magnetism in multisublattice magnets.

Findings

Quantitative agreement between THz emission and magneto-optical response in GdFeCo.

Faster THz emission dynamics compared to magneto-optical response in NdFeCo.

Orbital magnetism significantly influences ultrafast demagnetization processes.

Abstract

Simultaneous detection of THz emission and transient magneto-optical response is employed to study ultrafast laser-induced magnetization dynamics in multisublattice magnets NdFeCo and GdFeCo amorphous alloys with in-plane magnetic anisotropy. A satisfactory quantitative agreement between the dynamics revealed with the help of these two techniques is obtained for GdFeCo. For NdFeCo the THz emission reveals faster dynamics than the magneto-optical response. This indicates that in addition to spin dynamics of Fe ultrafast laser excitation triggers faster magnetization dynamics of Nd.