FisMat2017 - Submission - View

Abstract's title: Coherent magnons in antiferromagnetic thin films stimulated by EUV pulses from the seeded free-electron laser FERMI
Submitting author: Alberto Simoncig
Affiliation: Elettra Sincrotrone Trieste
Affiliation Address: Elettra-Sincrotrone Trieste S.C.p.A. Strada Statale 14 - km 163,5 in AREA Science Park 34149 Basovizza, Trieste (Italy)
Country: Italy
Oral presentation/Poster (Author's request): Poster
Other authors and affiliations: A. Simoncig (1), R. Mincigrucci (1), E. Principi (1), F. Bencivenga (1), A. Calvi (2), L. Foglia (1), G. Kurdi (1), L. Raimondi (1), M. Manfredda (1), N. Mahne (1), R. Gobessi (1), S. Gerusin (1), C. Fava (1), M. Zangrando (1), A. Matruglio (3), S. Dal Zilio (3), V. Masciotti (3), M. Lazzarino (3) and C. Masciovecchio (1) (1) Elettra Sincrotrone Trieste S. C. p. A. (2) Università degli Studi di Trieste (3) IOM (Istituto officina dei Materiali)

The full understanding of magnetism at the ultrafast (sub-picosecond) time-scale represents an open challenge for current material science and technology. We report the observation of coherent collective modes in the anti-ferromagnetic insulator nickel oxide (NiO), identified by the frequency expected for the out-of-plane single-mode magnon resonance of NiO. These magnetic collective excitations have been inelastically stimulated by extreme ultra-violet (EUV) pulses delivered by the seeded free-electron laser (FEL) FERMI (Trieste, Italy) and subsequently revealed probing the transient optical activity of NiO by means of well-known magneto-optical effects (Faraday effect). Additionally, we present the dependence of these modes as a function of the helicity of the incoming EUV photons. Similar processes have been reported by the table-top community where infrared or even longer wavelength (THz) pulses have been used to trigger such collective modes, but never, to our knowledge, in the EUV spectral range around transition core resonances. A phenomenological model has been purposely developed for qualitatively explaining the observed data. These results could push further the current knowledge of ultrafast magnetic processes and serve as a starting point for future and deeper investigations.