Ultrafast Time-Resolved Faraday Rotation in EuO Thin Films

TL;DR

This study explores ultrafast spin dynamics in EuO thin films using time-resolved Faraday rotation, revealing transient magnetization enhancement and demagnetization behaviors linked to exchange interactions.

Contribution

It demonstrates the observation of transient collective magnetic ordering and its temperature dependence in EuO thin films through ultrafast spectroscopy.

Findings

Transient magnetization increases following photoexcitation.

Maximum enhancement occurs just below the Curie temperature.

Magnetization enhancement decays in approximately 1 nanosecond.

Abstract

We have investigated the ultrafast spin dynamics in EuO thin films by time-resolved Faraday rotation spectroscopy. The photoinduced magnetization is found to be increased in a transient manner, accompanied with subsequent demagnetization. The dynamical magnetization enhancement showed a maximum slightly below the Curie temperature with prolonged tails toward both lower and higher temperatures and dominates the demagnetization counterpart at 55 K. The magnetization enhancement component decays in ~1 ns. The realization of the transient collective ordering is attributable to the enhancement of the f-d exchange interaction.