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MA: Magnetismus

MA 7: Micro- and Nanostructured Magnetic Materials I

MA 7.8: Vortrag

Montag, 27. März 2006, 16:45–17:00, HSZ 03

Neutron scattering and modeling of dipole-field-induced spin disorder in Nanoperm — •Andreas Michels¹, C. Vecchini², O. Moze², K. Suzuki³, P.K. Pranzas⁴, J. M. Cadogan⁵, and J. Weissmüller⁶ — ¹Technische Physik, Universität des Saarlandes, Saarbrücken, Germany — ²Physics Department, University of Modena and Reggio Emilia, Italy — ³Department of Materials Engineering, Monash University, Melbourne, Australia — ⁴GKSS Research Center, Geesthacht, Germany — ⁵School of Physics, University of New South Wales, Sydney, Australia — ⁶Institut für Nanotechnologie, Forschungszentrum Karlsruhe, Karlsruhe, Germany

We present temperature and magnetic-field-dependent small-angle neutron scattering data for the ferromagnetic nanocomposite Nanoperm (Fe₈₉Zr₇B₃Cu₁). The spin-misalignment scattering in the approach-to-saturation regime unexpectedly reveals pronounced lobes of high intensity at angles ±   30 − 40^∘ relative to the magnetic-field axis. Based on numerical calulations, the four-fold angular symmetry of the scattering pattern can be explained in terms of local spin misalignment, which originates from dipolar stray fields due to the mismatch of the saturation-magnetization values between the bcc Fe particles and the amorphous magnetic matrix.

[1] A. Michels et al., Europhys. Lett. 72, 249 (2005).

[2] C. Vecchini et al., Appl. Phys. Lett., in press (2005).