[en] The response of a colloidal dispersion of Ni nanorods to an oscillating magnetic field was characterized by optical transmission measurements as well as small-angle neutron scattering (SANS) experiments using the TISANE (Time-dependent SANS experiments) technique. Exposed to a static magnetic field, the scattering intensity of the rod ensemble could be well described by the cylinder form factor using the geometrical particle parameters (length, diameter, orientation distribution) determined by transmission electronmicroscopy and magnetometry. An oscillation of the field vector resulted in a reorientation of the nanorods and a time-dependency of the scattering intensity due to the shape anisotropy of the rods. Analysis of the SANS data revealed that in the range of low frequencies the orientation distribution of the rods is comparable to the static case. With increasing frequency, the rod oscillation was gradually damped due to an increase of the viscous drag. It could be shown that despite of the increased friction in the high frequency range no observable change of the orientation distribution of the ensemble with respect to its symmetry axis occurs.
Disciplines :
Physics
Author, co-author :
Bender, Philipp; Universität des Saarlandes > Experimentalphysik
Günther, Annegret ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit
Honecker, Dirk ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit
Wiedenmann, Albrecht; Institute Laue Langevin, Grenoble
Disch, Sabrina; Universität zu Köln > Institut für Physikalische Chemie > Department Chemie
Tschöpe, Andreas; Universität des Saarlandes > Experimentalphysik
Michels, Andreas ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit
Birringer, Rainer; Universität des Saarlandes > Experimentalphysik
External co-authors :
yes
Language :
English
Title :
Excitation of Ni nanorod colloids in oscillating magnetic fields: a new approach for nanosensing investigated by TISANE