Ultrafast electron transport in thin NiFe films on NiO

This work investigates pulse energy effects on the ultrafast dynamics of thin NiFe films on NiO. A detailed study of the electronic relaxation on this important model system for studying ultrafast magnetic behavior dynamics is presented. The NiFe alloy which is studied here is a permalloy for which the static magnetic properties have been well characterized. Pump-probe transient reflectivity measurements at λ = 800 nm, with 100 fs temporal resolution, have been performed on samples with NiFe thicknesses between 10 to 30 nm, also varying the incident pump pulse energies, in order to investigate the influence of the initial distribution on the electronic relaxation.