Jarecki, J.; Mattern, M.; Weber, F.C.; Pudell, J.E.; Wang, X.G.; Rojas Sánchez, J.C.; Hehn, M.; von Reppert, A.; Bargheer, M.: Controlling effective field contributions to laser-induced magnetization precession by heterostructure design. Communications Physics 7 (2024), p. 112/1-10
10.1038/s42005-024-01602-z
Open Access Version
Abstract:
Nanoscale heterostructure design can control laser-induced heat dissipation and strain propagation, as well as their efficiency for driving magnetization precession. Here, we incorporate MgO layers into the experimental platform of metallic Pt-Cu-Ni heterostructures to block the propagation of hot electrons. We show via ultrafast x-ray diffraction the capability of our platform to control the spatio-temporal shape of the transient heat and strain. Time-resolved magneto-optical Kerr experiments with systematic tuning of the magnetization precession frequency showcase control of the magnetization dynamics in the Ni layer. Our experimental analysis highlights the role of quasi-static strain as a driver of precession when the magnetic material is rapidly heated via electrons. The effective magnetic field change originating from demagnetization partially compensates the change induced by quasi-static strain. The strain pulses can be shaped via the nanoscale heterostructure design to efficiently drive the precession, paving the way for opto-magneto-acoustic devices with low heat energy deposited in the magnetic layer.