[en] Aqueous dispersions of nickel nanorods, ~13 nm in diameter and 40–160 nm in length, were
synthesized using ac electrodeposition into porous alumina templates. The nanorods in suspension can be aligned by modest magnetic fields, which leads to a change in the optical transmittance of the dispersion. Optical transmission measurements with polarized and unpolarized light as a function of magnetic field were performed on suspensions of different particle concentration and varying aspect ratio of the nanoparticles. The experimental results were compared with a theoretical model in which the optical absorption of the nanorods is calculated from the polarizability of prolate ellipsoids in the quasistatic approximation. The magnetic field dependence is introduced in terms of the static orientational distribution function of magnetic moments in an external field. In addition, the relaxation dynamics of the optical transmission was studied, which allowed us to determine the rotational diffusion coefficient of the nanorods in suspension.
Disciplines :
Physics
Author, co-author :
Klein, Tobias; Universität des Saarlandes, Saarbrücken, Germany > Technische Physik
Laptev, Aleksej; Universität des Saarlandes, Saarbrücken, Germany > Technische Physik
Günther, Annegret ; Universität des Saarlandes, Saarbrücken, Germany > Technische Physik
Bender, Philipp; Universität des Saarlandes, Saarbrücken, Germany > Technische Physik
Tschöpe, Andreas; Universität des Saarlandes, Saarbrücken, Germany > Technische Physik
Birringer, Rainer; Universität des Saarlandes, Saarbrücken, Germany > Technische Physik
Language :
English
Title :
Magnetic-field-dependent optical transmission of nickel nanorod colloidal dispersions
Publication date :
2009
Journal title :
Journal of Applied Physics
ISSN :
0021-8979
Publisher :
American Institute of Physics, Melville, United States - New York