  A new class of materials is developed that is a liquid with both high
conductivity and magnetic susceptibility for magnetohydrodynamic (MHD)
applications. We develop a general method for making such suspensions and
demonstrate that various magnetic and non-magnetic metal particles, from 40 nm
- 500 microns in diameter, can be suspended in liquid gallium and its alloys.
The method uses an acid solution to prevent oxidation of the liquid metal and
metallic particles, which allows wetting and thus suspending. We can increase
the magnetic permeability by a factor of 5.0 by controlling the packing
fraction of magnetic particles, which gives these materials the potential to
exhibit strong MHD effects on the laboratory scale that are usually only
observable in the cores of planets and stars. We can independently tune the
viscosity by a factor of 230 by adding non-magnetic particles, which would
allow independent control of MHD effects from turbulence.
