Regensburg 2013 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
MA: Fachverband Magnetismus
MA 17: Magnetic Particles and Clusters (jointly with CPP, BP)
MA 17.9: Talk
Tuesday, March 12, 2013, 12:15–12:30, H22
Rotational dynamics of Ni nanorod colloids characterized by optical transmission and neutron scattering — •Philipp Bender1, Albrecht Wiedenmann2, Annegret Günther3, Dirk Honecker3, Andreas Tschöpe1, and Rainer Birringer1 — 1Universität des Saarlandes, Saarbrücken, Germany — 2Institut Laue Langevin, Grenoble, France — 3University of Luxembourg, Luxembourg
With diameters below 42 nm, Ni nanorods are uniaxial ferromagnetic single-domain particles. When dispersed in a liquid matrix, alignment of their magnetic moments along an external magnetic field is achieved by a rotation of the entire particle. In time-modulated magnetic fields the switching dynamics depends on the viscous friction of the nanorods in the liquid matrix. Due to the anisotropic electrical polarizability optical transmission measurements can be used to detect the response of a colloidal dispersion of Ni nanorods to a rotating magnetic field. In particular, the rotational diffusion coefficient can be extracted from the phase shift between the periodic variation of the rotating magnetic field and the resulting oscillation in the optical transmission. In the present study Small Angle Neutron Scattering (SANS) is used in addition to the transmission of polarized light to experimentally determine the hydrodynamic interactions of Ni nanorods with the liquid matrix in a rotating magnetic field.