Mattern, M.; Pudell, J.-E.; Arregi, J.A.; Zlámal, J.; Kalousek, R.; Uhlír, V.; Rössle, M.; Bargheer, M.: Accelerating the Laser-Induced Phase Transition in Nanostructured FeRh via Plasmonic Absorption. Advanced Functional Materials 34 (2024), p. 2313014/1-10
10.1002/adfm.202313014
Open Access Version
Abstract:
By ultrafast x-ray diffraction (UXRD), it is shown that the laser-induced magnetostructural phase transition in FeRh nanoislands proceeds faster and more complete than in continuous films. An intrinsic 8 ps timescale is observed for the nucleation of ferromagnetic (FM) domains in the optically excited fraction of both types of samples. For the continuous film, the substrate-near regions are not directly exposed to light and are only slowly transformed to the FM state after heating above the transition temperature via near-equilibrium heat transport. Numerical modeling of the absorption in the investigated nanoislands reveals a strong plasmonic contribution near the FeRh/MgO interface. The larger absorption and the optical excitation of the electrons in nearly the entire volume of the nanoislands enables a rapid phase transition throughout the entire volume at the intrinsic nucleation timescale.