Ultrafast optical control of magnetization in EuO thin films

TL;DR

This study demonstrates ultrafast optical control of magnetization in EuO thin films using circularly-polarized light, revealing nonthermal photomagnetic effects within 100 femtoseconds.

Contribution

It shows that circularly-polarized light can control magnetization precession in EuO films via nonthermal effects on an ultrafast timescale.

Findings

Magnetization precession can be controlled within 100 fs.

The intrinsic Gilbert damping coefficient is approximately 3×10^-3.

Circularly-polarized light induces nonthermal photomagnetic effects.

Abstract

All-optical pump-probe detection of magnetization precession has been performed for ferromagnetic EuO thin films at 10 K. We demonstrate that the circularly-polarized light can be used to control the magnetization precession on an ultrafast time scale. This takes place within the 100 fs duration of a single laser pulse, through combined contribution from two nonthermal photomagnetic effects, i.e., enhancement of the magnetization and an inverse Faraday effect. From the magnetic field dependences of the frequency and the Gilbert damping parameter, the intrinsic Gilbert damping coefficient is evaluated to be {\alpha} \approx 3\times10^-3.