Labyrinthine instability in magnetic fluids revisited

The field-induced formation of labyrinthine patterns is studied theoretically. A theory proposed by Rosensweig, Zahn and Shumovich (J. Magn. Magn. Mater. 1983, 39, 127) for the spacing of the labyrinthine strips is corrected. At low magnetic fields, the corrected theory predicts the strip widths in good agreement with experiment. At high fields, there is a discrepancy between theory and experiment that is attributed to the approximations inherent in the theoretical approach. A more accurate theory is proposed that correctly describes the experimental decrease in strip widths on increasing the field.