Accelerating the laser-induced phase transition in nanostructured FeRh via plasmonic absorption

TL;DR

This study demonstrates that nanostructuring FeRh enhances the speed and completeness of laser-induced phase transitions by leveraging plasmonic absorption, leading to more uniform and rapid magnetic state changes.

Contribution

It shows that nanostructuring FeRh with plasmonic effects accelerates and homogenizes the phase transition compared to continuous films, revealing a new pathway for ultrafast magnetic control.

Findings

Nanostructured FeRh exhibits faster phase transition than continuous films.

Plasmonic absorption enhances and homogenizes energy delivery in nanoislands.

Intrinsic nucleation timescale of 8 ps observed in both samples.

Abstract

By ultrafast x-ray diffraction we show that the laser-induced magnetostructural phase transition in FeRh nanoislands proceeds faster and more complete than in continuous films. We observe an intrinsic 8 ps timescale for nucleation of ferromagnetic (FM) domains in both types of samples. For the continuous film, the substrate-near regions, which are not directly exposed to light, are only slowly transformed to the FM state by domain wall motion following heat transport. In contrast, numerical modeling of the plasmonic absorption in the investigated nanostructure reveals a strong contribution near the FeRh/MgO interface. On average, the absorption is larger and more homogeneous in the nanoislands, enabling the phase transition throughout the entire volume at the intrinsic nucleation timescale.