Spectral dependence of photoinduced spin precession in DyFeO3

TL;DR

This study investigates how ultrashort laser pulses induce spin precession in DyFeO3, revealing spectral dependence and distinguishing between inverse Faraday and Cotton-Mouton effects through phase analysis.

Contribution

It provides the first combined theoretical and experimental analysis of spectral dependence of photoinduced spin precession mechanisms in DyFeO3.

Findings

Inverse Faraday effect dominates in visible spectrum

Inverse Cotton-Mouton effect becomes prominent in near-infrared

Same spin precession mode is excited by different polarization states

Abstract

Spin precession was nonthermally induced by an ultrashort laser pulse in orthoferrite DyFeO3 with a pump-probe technique. Both circularly and linearly polarized pulses led to spin precessions; these phenomena are interpreted as the inverse Faraday effect and the inverse Cotton-Mouton effect, respectively. For both cases, the same mode of spin precession was excited; the precession frequencies and polarization were the same, but the phases of oscillations were different. We have shown theoretically and experimentally that the analysis of phases can distinguish between these two mechanisms. We have demonstrated experimentally that in the visible region, the inverse Faraday effect was dominant, whereas the inverse Cotton-Mouton effect became relatively prominent in the near-infrared region.