Element Selective Probe of the Ultra-Fast Magnetic Response to an Element Selective Excitation in Fe-Ni Compounds Using a Two-Color FEL Source
oleh: Eugenio Ferrari, Carlo Spezzani, Franck Fortuna, Renaud Delaunay, Franck Vidal, Ivaylo Nikolov, Paolo Cinquegrana, Bruno Diviacco, David Gauthier, Giuseppe Penco, Primož Rebernik Ribič, Eléonore Roussel, Mauro Trovò, Jean-Baptiste Moussy, Tommaso Pincelli, Lounès Lounis, Cristian Svetina, Marco Zangrando, Nicola Mahne, Lorenzo Raimondi, Michele Manfredda, Emanuele Pedersoli, Flavio Capotondi, Alexander Demidovich, Luca Giannessi, Maya Kiskinova, Giovanni De Ninno, Miltcho Boyanov Danailov, Enrico Allaria, Maurizio Sacchi
| Format: | Article |
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| Diterbitkan: | MDPI AG 2017-01-01 |
Deskripsi
The potential of the two-color mode implemented at the FERMI free-electron laser (FEL) source for pumping and probing selectively different atomic species has been demonstrated by time-resolved scattering experiments with permalloy (FeNi alloy) and NiFe2O4 samples. We monitored the ultra-fast demagnetization of Ni induced by the pump FEL pulse, by tuning the linearly-polarized FEL probe pulse to the Ni-3p resonance and measuring the scattered intensity in the transverse magneto-optical Kerr effect geometry. The measurements were performed by varying the intensity of the FEL pump pulse, tuning its wavelength to and off of the Fe-3p resonance, and by spanning the FEL probe pulse delays across the 300–900 fs range. The obtained results have evidenced that for the case of NiFe2O4, there is a sensible difference in the magnetic response at the Ni site when the pump pulse causes electronic excitations at the Fe site.