Parametrically excited surface waves in magnetic fluids: observation of   domain structures
  Observations of parametrically excited surface waves in a magnetic fluid are presented. Under the influence of a magnetic field these waves have a non--monotonic dispersion relation, which leads to a richer behavior than in ordinary liquids. We report observation of three novel effects, namely:   i) domain structures,   ii) oscillating defects and   iii) relaxational phase oscillations. 
Thomas Mahr and Ingo Rehberg (Universitaet Magdeburg, Germany)