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

Thu 811:10-14:00P8.11Dynamics of suspensions of anisotropic colloidalparticles investigated by X-Ray Photon CorrelationSpectroscopyLouisa Dahbi, 1 Heiko Conrad, 1 Ingo Steinke, 1 Felix Lehmkühler, 1 MichaelSprung, 1 and Gerhard Grübel 11 Hasylab at DESY- Deutsches Elektronen Synchrotron, Notkestrasse 85, 22607,Hamburg, GermanyThe slow dynamics of glass forming systems close to the glass transition results in differentrelaxation mechanisms [1]. By means of X-Ray photon correlation spectroscopy (XPCS) [2, 3]we investigate the dynamics of suspensions of anisotropic spindle-type hematites (α − Fe 2 O 3 )when their dynamics is slowed down by reducing the temperature close to the glassy state.Anisotropic hematites are of special relevance due to their properties to align perpendicularly toa magnetic field, which leads to the quench to one degree of motion. Two kinds of experimentswere performed. In the first kind of experiment, the only external parameter is temperature, whilein the second type of experiment a constant magnetic field is applied as additional parameter. Therotational motion of the particle in then allowed only around the easy axis of magnetization that isperpendicular to the spindle axis. We will expose how the dynamics of the particles is governedby temperature and how the magnetic field affects the dynamics of the suspension.[1] M. D. Edinger, C. A. Angell, S. R. Nagel, J. Phys. Chem. , 100, 13, 200 (1996)[2] G. Grübel, D. Abernathy, D. Riese, W. Vos, G. Wegdam, J. Appl. Cryst. , 33, 1 (2000)[3] A. Robert, E. Wandersman, E. Dubois, V. Dupuis, R. Perzynski, Eur. Letters (2006)11