Domain formation and long-range spin disorder in Vitroperm
Institut für Nanotechnologie, Forschungszentrum Karlsruhe - Karlsruhe, Germany
2 Technische Physik, Universität des Saarlandes - Saarbrücken, Germany
Accepted: 23 July 2003
We present a study of the magnetic-field dependence of the small-angle neutron scattering of the nanocrystalline soft magnet Vitroperm (), which was treated so as to exhibit a macroscopic magnetic anisotropy. We show how the field dependences of i) the radial average of the scattering cross-section and ii) the variation of as a function of the orientation of the scattering vector can be analysed to supply separately information on the orientation of the net magnetisation of the domains and on the internal spin disorder within the domains. As the applied magnetic field is decreased starting from saturation, we find that two processes occur independently: the formation of a domain structure with the net magnetisation of the domains aligned along the macroscopic easy axis and the increase in magnitude of static, nanometer-scale fluctuations of the spin orientation.
PACS: 61.12.Ex – Neutron scattering (including small-angle scattering) / 75.50.Tt – Fine-particle systems; nanocrystalline materials / 75.75.+a – Magnetic properties of nanostructures
© EDP Sciences, 2003