title: Indirect excitation of ultrafast demagnetization.
abstract: Does the excitation of ultrafast magnetization require direct interaction between the photons of the optical pump pulse and the magnetic layer? Here, we demonstrate unambiguously that this is not the case. For this we have studied the magnetization dynamics of a ferromagnetic cobalt/palladium multilayer capped by an IR-opaque aluminum layer. Upon excitation with an intense femtosecond-short IR laser pulse, the film exhibits the classical ultrafast demagnetization phenomenon although only a negligible number of IR photons penetrate the aluminum layer. In comparison with an uncapped cobalt/palladium reference film, the initial demagnetization of the capped film occurs with a delayed onset and at a slower rate. Both observations are qualitatively in line with energy transport from the aluminum layer into the underlying magnetic film by the excited, hot electrons of the aluminum film. Our data thus confirm recent theoretical predictions.
authors.affiliation: Sorbone Universités, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France.|CNRS, UMR 7614, LCPMR, 75005 Paris, France.
authors.forename: Boris
authors.initials: B
authors.lastname: Vodungbo
authors.forename: Bharati
authors.initials: B
authors.lastname: Tudu
authors.affiliation: Sorbone Universités, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France.|CNRS, UMR 7614, LCPMR, 75005 Paris, France.
authors.forename: Bahrati
authors.initials: B
authors.lastname: Tudu
authors.affiliation: Sorbone Universités, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France.|CNRS, UMR 7614, LCPMR, 75005 Paris, France.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Perron
authors.affiliation: Sorbone Universités, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France.|CNRS, UMR 7614, LCPMR, 75005 Paris, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: Delaunay
authors.affiliation: Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany.
authors.forename: Leonard
authors.initials: L
authors.lastname: Müller
authors.affiliation: Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany.
authors.forename: Magnus H
authors.initials: MH
authors.lastname: Berntsen
authors.affiliation: Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany.|The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Grübel
authors.affiliation: Institut Jean Lamour, UMR CNRS 7198 - Université de Lorraine - boulevard des aiguillettes BP 70239, Vandoeuvre cedex F-54506 France.
authors.forename: Grégory
authors.initials: G
authors.lastname: Malinowski
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), JARA- FIT, 52425 Jülich, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Weier
authors.affiliation: LOA, ENSTA ParisTech, CNRS, Ecole polytechnique, Université Paris-Saclay, 828 bd des Maréchaux, 91762 Palaiseau cedex France.
authors.forename: Julien
authors.initials: J
authors.lastname: Gautier
authors.affiliation: LOA, ENSTA ParisTech, CNRS, Ecole polytechnique, Université Paris-Saclay, 828 bd des Maréchaux, 91762 Palaiseau cedex France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Lambert
authors.affiliation: LOA, ENSTA ParisTech, CNRS, Ecole polytechnique, Université Paris-Saclay, 828 bd des Maréchaux, 91762 Palaiseau cedex France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Zeitoun
authors.affiliation: Department Physik, Universität Siegen, Walter-Flex-Str. 3, 57072 Siegen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Gutt
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Jal
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors.forename: Alexander H
authors.initials: AH
authors.lastname: Reid
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.|Van der Waals-Zeeman Institute, University of Amsterdam, 1018XE Amsterdam, The Netherlands.
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Granitzka
authors.affiliation: Synchrotron SOLEIL, Saint-Aubin, Boîte Postale 48, 91192 Gif-sur-Yvette Cedex, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Jaouen
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors.forename: Georgi L
authors.initials: GL
authors.lastname: Dakovski
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors.forename: Stefan
authors.initials: S
authors.lastname: Moeller
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Minitti
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors.forename: Ankush
authors.initials: A
authors.lastname: Mitra
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Carron
authors.affiliation: Division of Synchrotron Radiation Research, Lund University, Box 118, 22100 Lund, Sweden.
authors.forename: Bastian
authors.initials: B
authors.lastname: Pfau
authors.affiliation: Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin, Germany.
authors.forename: Clemens
authors.initials: C
authors.lastname: von Korff Schmising
authors.affiliation: Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Schneider
authors.affiliation: Division of Synchrotron Radiation Research, Lund University, Box 118, 22100 Lund, Sweden.|Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Eisebitt
authors.affiliation: Sorbone Universités, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France.|CNRS, UMR 7614, LCPMR, 75005 Paris, France.|Synchrotron SOLEIL, Saint-Aubin, Boîte Postale 48, 91192 Gif-sur-Yvette Cedex, France.
authors.forename: Jan
authors.initials: J
authors.lastname: Lüning