title: The spin and orbital contributions to the total magnetic moments of free Fe, Co, and Ni clusters.
abstract: We present size dependent spin and orbital magnetic moments of cobalt (Con (+), 8 ≤ n ≤ 22), iron (Fen (+), 7 ≤ n ≤ 17), and nickel cluster (Nin (+), 7 ≤ n ≤ 17) cations as obtained by X-ray magnetic circular dichroism (XMCD) spectroscopy of isolated clusters in the gas phase. The spin and orbital magnetic moments range between the corresponding atomic and bulk values in all three cases. We compare our findings to previous XMCD data, Stern-Gerlach data, and computational results. We discuss the application of scaling laws to the size dependent evolution of the spin and orbital magnetic moments per atom in the clusters. We find a spin scaling law "per cluster diameter," ∼n(-1/3), that interpolates between known atomic and bulk values. In remarkable contrast, the orbital moments do likewise only if the atomic asymptote is exempt. A concept of "primary" and "secondary" (induced) orbital moments is invoked for interpretation.
authors.affiliation: Fachbereich Chemie and Forschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Meyer
authors.affiliation: Fachbereich Chemie and Forschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Tombers
authors.affiliation: Fachbereich Chemie and Forschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: van Wüllen
authors.affiliation: Fachbereich Chemie and Forschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.
authors.forename: Gereon
authors.initials: G
authors.lastname: Niedner-Schatteburg
authors.affiliation: Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany and DESY-CFEL, Notkestr. 85, 22607 Hamburg, Germany.
authors.forename: Sergey
authors.initials: S
authors.lastname: Peredkov
authors.affiliation: Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany and DESY-CFEL, Notkestr. 85, 22607 Hamburg, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Eberhardt
authors.affiliation: Helmholtz-Zentrum für Materialien und Energie, BESSY II, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Neeb
authors.affiliation: Institut für Experimentalphysik, Universität Hamburg, Luruper Chausee 149, 22761 Hamburg, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Palutke
authors.affiliation: Institut für Experimentalphysik, Universität Hamburg, Luruper Chausee 149, 22761 Hamburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Martins
authors.affiliation: Institut für Experimentalphysik, Universität Hamburg, Luruper Chausee 149, 22761 Hamburg, Germany.
authors.forename: Wilfried
authors.initials: W
authors.lastname: Wurth