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MA: Fachverband Magnetismus

MA 36: Magnetization and Demagnetization Dynamics III

MA 36.3: Talk

Wednesday, March 9, 2016, 15:30–15:45, H34

Relevance of the exchange coupling in ultrafast demagnetization of ferromagnetic alloys — •Stefan Günther^1,12, Carlo Spezzani^2,11, Roberta Ciprian³, Cesare Grazioli^2,4, Barbara Ressel⁴, Marcello Coreno^2,5, Luca Poletto⁶, Paolo Miotti⁶, Maurizio Sacchi^7,8,9, Giancarlo Panaccione³, Vojtěch Uhlíř¹⁰, Eric E. Fullerton¹⁰, Giovanni De Ninno^2,4, Christian H. Back¹, and Manfred Fiebig¹² — ¹University of Regensburg — ²Elettra Sincrotrone Trieste — ³IOM-CNR, Triest — ⁴University of Nova Gorica — ⁵CNR-IMIP, Rome — ⁶CNR-IFN, Padova — ⁷Sorbonne Universités, Paris — ⁸Centre national de la recherche scientifique, Paris — ⁹Synchrotron SOLEIL, Saint-Aubin — ¹⁰University of California, San Diego — ¹¹University Paris Sud — ¹²ETH Zürich

We use element-resolved infrared-pump/extreme ultraviolet-probe experiments to disentangle the ultrafast interplay of magnetic alloys during ultrafast demagnetization. As paradigmatic examples, we investigate the cases of the FeRh alloy (crystalline and ordered), FeCo alloy (crystalline but disordered) and FeNi alloy (polycrystalline). All three systems reveal different dynamics for the alloy's components and a distinct time difference in the onset of the demagnetization is observed. The magnitude of this temporal delay is related to the interatomic exchange interaction for all three systems where the mismatch of the demagnetization traces decreases with stronger coupling.