Magnetically driven assembly of superparamagnetic colloidal particles

Abstract

Thin ferromagnetic film patterned into isolated islands is used to direct assembly of superparamagnetic colloidal particles into two-dimensional arrays. Ferromagnetic islands positioned under a template of micro-wells are shown to promote highly regular 2D arrays, while external uniform magnetic field is used to bias the particles to attract or repel from the exposed end of the ferromagnetic islands. A theoretical analysis on the interactions between superparamagnetic colloidal particles with the template and external uniformmagnetic fields is also presented