title: Real space trajectory of the ultrafast magnetization dynamics in ferromagnetic metals.
abstract: We have measured the real space trajectory of the ultrafast magnetization dynamics in ferromagnetic metals induced by femtosecond optical pulses. Our approach allows the observation of the initial change of the modulus and orientation of the magnetization, occurring within a few hundreds of femtoseconds, as well as its subsequent precession and damping around the effective field. The role of the magnetocrystalline anisotropy shows up in the magnetization reorientation occurring during the electron-lattice relaxation. In addition, we propose a model which takes into account the initial demagnetization in the Bloch formalism describing the magnetization dynamics.
authors.affiliation: Institut de Physique et Chimie des Matériaux de Strasbourg, Unité Mixte 7504 CNRS, Université Louis Pasteur BP. 43, 23 rue du Loess, 67034 Strasbourg Cedex, France.
authors.forename: M
authors.initials: M
authors.lastname: Vomir
authors.forename: L H F
authors.initials: LH
authors.lastname: Andrade
authors.forename: L
authors.initials: L
authors.lastname: Guidoni
authors.forename: E
authors.initials: E
authors.lastname: Beaurepaire
authors.forename: J-Y
authors.initials: JY
authors.lastname: Bigot