Magnetically directed self-assembly of submicron spheres with a Fe3O4 nanoparticle shell

Abstract

A grid of micrometer-sized core-shell particles was fabricated by magnetophoretic deposition using a water-based colloidal solution. The core-shell particles consist of a 640 nm diameter polystyrene spherical core covered with a shell of five layers of 12 nm diameter Fe3O4 nanocrystals. The separation and the length of the individual chains can be tuned by the magnetic field strength and the concentration of the particle solution. The magnetic properties were characterized by angular-dependent ferromagnetic resonance and SQUID magnetometry. © 2002 Elsevier Science B.V. All rights reserved.