Studies of mesoscopic lattices forming with magnetic fluid

The high-quality magnetic fluid composition is capable of forming two-dimen sional lattices of concentrated magnetic particle columns in a thin film in magnetic fields. The extraordinary lattices, a kind of novel mesoscopic sy stem, have been explored with optical microscopy, digital imaging, and comp uter-video technique in this study. The two-dimensional lattices present he xagonal phase with exotic topological defects due to the structure distorti on under excitations. The ordering of the 2D lattices are classified with p ositional and bond-orientational correlation functions. Some dynamical obse rvations of topological defects are also made in this study. (C) 2000 Elsev ier Science B.V. All rights reserved.