Simultaneous electronic and the magnetic excitation of a ferromagnet by intense THz pulses

TL;DR

This paper demonstrates that intense THz pulses can simultaneously excite electronic and magnetic responses in cobalt thin films, with the electric response persisting much longer than the magnetic one, revealing new dynamics in ultrafast magnetization control.

Contribution

It reveals the concurrent electronic and magnetic excitations induced by intense THz pulses in ferromagnetic cobalt, highlighting the role of the electric field at high intensities.

Findings

Electric field significantly alters dielectric properties at high THz intensities.

Electronic and magnetic responses occur simultaneously.

Electric response persists much longer than the THz pulse duration.

Abstract

The speed of magnetization reversal is a key feature in magnetic data storage. Magnetic fields from intense THz pulses have been recently shown to induce small magnetization dynamics in Cobalt thin film on the sub-picosecond time scale. Here, we show that at higher field intensities, the THz electric field starts playing a role, strongly changing the dielectric properties of the cobalt thin film. Both the electronic and magnetic responses are found to occur simultaneously, with the electric field response persistent on a time scale orders of magnitude longer than the THz stimulus