Ultrafast EUV Spectroscopy of Ferromagnetic Multilayers

Probing spin dynamics in magnetic materials on their fundamental space, time, and energy scales provides new insights into the strongly-coupled interactions of the spin, charge, and lattice orders. These interactions govern both the equilibrium and excited state dynamics, but they are still poorly understood and thus challenging to control. In past work we showed that ultrafast light induced quenching of the magnetic state has contributions from both spin flips and from spin transport. Here we present ultrafast EUV spectroscopic measurements demonstrating that it is possible to partially suppress laser induced demagnetization in a ferromagnetic thin film by placing a chromium thin film underneath it. The suppression may occur through the reflection of spin currents, which otherwise play an important role in laser induced demagnetization. The suppression of specific demagnetization channels may be a useful tool for tailoring ultrafast magneto-optic interactions.