8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Tue 611:23-14:00P10.27Magnetic birefringence of biogenic ferrritins and theirmimeticsMikolaj Pochylski 1 and Marceli Koralewski 11 Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614, Poznan,PolandThe static birefringence of dilute monodisperse ferrofluid exposed to external magnetic fieldresults from the orientation of optically anisotropic particles along the magnetic field direction.The degree of orientation depends on the energy related with the interaction between particle’smagnetic moments (both induced and/or permanent) and the magnetic field. The magnetic energyassociated with the dipole moment depends mostly on the size of the particle and the magnetizationof its material. Thus, magnetic field induced birefringence can be the effect potentiallyable for discrimination between magnetic core structures of biologically relevant iron-storingcompounds [1]. We presents results of magnetic birefringence measurements performed withbiogenic ferritin (i. e. horse spleen ferritin), synthetic ferritin (magnetoferritin), model nanoscalemagnetite, iron-dextran complex, as well as some mixture modelling a heterogeneous structure ofbiogenic brain ferritin. The results obtained are discussed in frame of the Langevin formalism ofdipolar orientation. The applicability of the Cotton-Mouton constant (derived from low magneticfield region) is also examined.[1] M. Koralewski, M. Pochylski, J. Gierszewski, J. Magn. Magn. Mater. 323, 1140(2011)27