Anomalous Dynamics of Magnetic Anisotropic Colloids Studied by XPCS

Research output: Contribution to journalArticle


The influence of an applied magnetic field on the collective dynamics of novel anisotropic colloidal particles whose shape resembles peanuts is reported. Being made up of hematite cores and silica shells, these micrometer-sized particles align in a direction perpendicular to the applied external magnetic field, and assemble into chains along the field direction. The anisotropic dynamics of these particles is investigated using multispeckle ultrasmall-angle X-ray photon correlation spectroscopy (USA-XPCS). The results indicate that along the direction of the magnetic field, the particle dynamics strongly depends on the length scale probed. Here, the relaxation of the intermediate scattering function follows a compressed exponential behavior at large distances, while it appears diffusive at distances comparable or smaller than the particle size. Perpendicular to the applied field (and along the direction of gravity), the experimental data can be quantitatively reproduced by a combination of an advective term originating from sedimentation and a purely diffusive one that describes the thermal diffusion of the assembled chains and individual particles.


External organisations
  • European Synchrotron Radiation Facility
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Materials Chemistry
  • Physical Chemistry


  • anisotropic collective dynamics, anisotropic magnetic colloids, magnetic field–driven self-assembly, XPCS
Original languageEnglish
Article number1802233
Issue number46
Publication statusPublished - 2018
Publication categoryResearch