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  Jana, S.; Muralidhar, S.; Åkerman, J.; Schüßler-Langeheine, C.; Pontius, N.: Using the photoinduced L₃ resonance shift in Fe and Ni as time reference for ultrafast experiments at low flux soft x-ray sources. Structural Dynamics 8 (2021), p. 044304/1-7

10.1063/4.0000108
Open Accesn Version

Abstract:
We study the optical-pump induced ultrafast transient change of x-ray absorption at L3 absorption resonances of the transition metals Ni and Fe in the Fe0.5Ni0.5 alloy. We find the effect for both elements to occur simultaneously on a femtosecond timescale. This effect may hence be used as a handy cross correlation scheme, providing a time-zero reference for ultrafast optical-pump soft x-ray-probe measurement. The method benefits from a relatively simple experimental setup as the sample itself acts as time-reference tool. In particular, this technique works with low flux ultrafast soft x-ray sources. The measurements are compared to the cross correlation method introduced in an earlier publication.