Micro cog-wheels induced by a magnetic instability by a magnetic instability in a microdrop of ferrofluidE. Janiaud, F. Elias, J.-C. Bacri, V. Cabuil and R. PersynskiMatériaux & Techniques, 90 (2002) 9-12DOI: https://doi.org/10.1051/mattech/200290120009s