Probing ultrafast changes of spin and charge density profiles with resonant XUV magnetic reflectivity at the free-electron laser FERMI

• Published in: Structural dynamics (Melville, N.Y.) Vol. 4; no. 5; p. 055101
• Main Authors: Gutt, C., Sant, T., Ksenzov, D., Capotondi, F., Pedersoli, E., Raimondi, L., Nikolov, I. P., Kiskinova, M., Jaiswal, S., Jakob, G., Kläui, M., Zabel, H., Pietsch, U.
• Format: Journal Article
• Language: English
• Published: United States American Institute of Physics, Inc 01.09.2017; American Crystallographic Association; AIP Publishing LLC and ACA
• Subjects: Approximation; Asymmetry; Atoms & subatomic particles; Charge density; Circular polarization; Energy; Experiments; Ferrous alloys; Free electron lasers; Laser pumping; Lasers; Light; Magnetic alloys; Radiation; Reflectance; X-rays
• ISSN: 2329-7778; 2329-7778
• DOI: 10.1063/1.4990650

We report the results of resonant magnetic XUV reflectivity experiments performed at the XUV free-electron laser FERMI. Circularly polarized XUV light with the photon energy tuned to the Fe M2,3 edge is used to measure resonant magnetic reflectivities and the corresponding Q-resolved asymmetry of a Permalloy/Ta/Permalloy trilayer film. The asymmetry exhibits ultrafast changes on 240 fs time scales upon pumping with ultrashort IR laser pulses. Depending on the value of the wavevector transfer Qz , we observe both decreasing and increasing values of the asymmetry parameter, which is attributed to ultrafast changes in the vertical spin and charge density profiles of the trilayer film.