Ferro fluid, magnetic liquid

Ferro Fluid is a collodial suspension of nano scale magnetic particles in a liquid carrier. The particles average about 10nm in size and are coated with a dispersing agent (surfactant) to prevent agglomeration. Normally the particles arerandomly distributed,but in the presence of a magnetic field,each particle aligns along the magnetic force lines so that the fluid behaves as a homogenous magnetic liquid that responds  in the strength and orientation of the magnetic field.