title: Magnetic field-dependent spin structures of nanocrystalline holmium.
abstract: The results are reported of magnetic field-dependent neutron diffraction experiments on polycrystalline inert-gas condensed holmium with a nanometre crystallite size (D= 33 nm). AtT= 50 K, no evidence is found for the existence of helifan(3/2) or helifan(2) structures for the nanocrystalline sample, in contrast with results reported in the literature for the single crystal. Instead, when the applied fieldHis increased, the helix pattern transforms progressively, most likely into a fan structure. It is the component ofHwhich acts on the basal-plane spins of a given nanocrystallite that drives the disappearance of the helix; for nanocrystalline Ho, this field is about 1.3 T, and it is related to a characteristic kink in the virgin magnetization curve. For a coarse-grained Ho sample, concomitant with the destruction of the helix phase, the emergence of an unusual angular anisotropy (streak pattern) and the appearance of novel spin structures are observed.
authors.affiliation: Physics and Materials Science Research Unit, University of Luxembourg, 162A Avenue de la Faïencerie, L-1511 Luxembourg, Luxembourg.
authors.forename: Philipp
authors.initials: P
authors.lastname: Szary
authors.affiliation: Physics and Materials Science Research Unit, University of Luxembourg, 162A Avenue de la Faïencerie, L-1511 Luxembourg, Luxembourg.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kaiser
authors.affiliation: Physics and Materials Science Research Unit, University of Luxembourg, 162A Avenue de la Faïencerie, L-1511 Luxembourg, Luxembourg.
authors.forename: Jens-Peter
authors.initials: JP
authors.lastname: Bick
authors.affiliation: Zentrum für Material- und Küstenforschung GmbH, Helmholtz-Zentrum Geesthacht, Max-Planck-Straße 1, D-21502 Geesthacht, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Lott
authors.affiliation: Zentrum für Material- und Küstenforschung GmbH, Helmholtz-Zentrum Geesthacht, Max-Planck-Straße 1, D-21502 Geesthacht, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Heinemann
authors.affiliation: Large Scale Structures Group, Institut Laue-Langevin, 71 Avenue des Martyrs, SB 335, F-38042 Grenoble, France.
authors.forename: Charles
authors.initials: C
authors.lastname: Dewhurst
authors.affiliation: Experimentalphysik, Universität des Saarlandes, D-66041 Saarbrücken, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Birringer
authors.affiliation: Physics and Materials Science Research Unit, University of Luxembourg, 162A Avenue de la Faïencerie, L-1511 Luxembourg, Luxembourg.
authors.forename: Andreas
authors.initials: A
authors.lastname: Michels
keywords: magnetic materials; nanocrystalline holmium; neutron diffraction; rare earth metals; spin structures