C Gollwitzer et al 2006 J. Phys.: Condens. Matter 18 S2643 doi:10.1088/0953-8984/18/38/S08
C Gollwitzer, I Rehberg and R Richter
Show affiliationsWe report on different surface patterns on magnetic liquids following the Rosensweig instability. We compare the bifurcation from the flat surface to a hexagonal array of spikes with the transition to squares at higher fields. From a radioscopic mapping of the surface topography we extract amplitudes and wavelengths. For the hexagon–square transition, which is complex because of coexisting domains, we tailor a set of order parameters like peak-to-peak distance, circularity, angular correlation function and pattern specific amplitudes from Fourier space. These measures enable us to quantify the smooth hysteretic transition. Voronoi diagrams indicate a pinning of the domains. Thus the smoothness of the transition is roughness on a small scale.
47.54.-r Pattern selection; pattern formation
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
Issue 38 (27 September 2006)
Received 30 April 2006, in final form 26 July 2006
Published 8 September 2006
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