Ferrofluids—magnetically controlled suspensions

Suspensions of magnetic nanoparticles exhibit normal liquid behaviour coupled with superparamagnetic properties. This leads to the possibility to control the properties and the flow of these liquids with moderate magnetic fields. The magnetic control enables the design of various applications as well as basic experiments in hydrodynamics. Ferrofluids and their general properties will be introduced and as an example the control of their viscous properties by means of magnetic fields will be discussed to show the potential of magnetic fluid control.