PERIODIC STRUCTURES AND SCALING LAWS IN A MAGNETIC COLLOID

Phase separation was found in an eicosane-based ferrofluid in zero app lied field. Upon applying a magnetic field, the-condensed phase breaks up to form a lattice of periodic columns. The periodicity lambda scal es with the layer thickness L. Two scaling regimes were found. When th ickness is small, where no branching is observed, lambda proportional to L(1/2). In the large-thickness regime, a tree type of structure dev elops at the tail of each column, and the columns are separated by sid e bands while the scaling relation crosses over to lambda proportional to L(2/3).