title: Magnetic microrods as a tool for microrheology.
abstract: Dynamics of superparamagnetic rods in crossed constant and alternating magnetic fields as a function of field frequency are studied and it is shown that above the critical value of the amplitude of the alternating field the rod oscillates around the direction of the alternating field. The fit of the experimentally measured time dependence of the mean orientation angle of the rod allows one to determine the ratio of magnetic and viscous torques which act on the rod. The protocol of microrheological measurements consists of recording the dynamics of the orientation of the rod when the magnetic field is applied at an angle to the rod and observing its relaxation due to the accumulated elastic energy after the field is switched off. The microrheological data obtained are in reasonable agreement with the macrorheological measurements.
authors.affiliation: Faculty of Physics and Mathematics, University of Latvia, Zeļļu-8, Rīga, LV-1021, Latvia. aceb@tok.sal.lv.
authors.forename: Artis
authors.initials: A
authors.lastname: Brasovs
authors.forename: Jānis
authors.initials: J
authors.lastname: Cīmurs
authors.forename: Kaspars
authors.initials: K
authors.lastname: Ērglis
authors.forename: Andris
authors.initials: A
authors.lastname: Zeltins
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Berret
authors.forename: Andrejs
authors.initials: A
authors.lastname: Cēbers
mesh_terms: D004548:Elasticity; D004560:Electricity; D059346:Magnets; D055616:Microtechnology / Q000379:methods*; D008962:Models, Theoretical; D012212:Rheology / Q000379:methods*; D014783:Viscosity