1 Magnetic Systems, Department of Micro- and Nanotechnology, Technical University of Denmark2 Department of Micro- and Nanotechnology, Technical University of Denmark3 Microreactors, Department of Micro- and Nanotechnology, Technical University of Denmark4 Center for Individual Nanoparticle Functionality, Center, Technical University of Denmark5 unknown6 Experimental Surface and Nanomaterials Physics, Department of Physics, Technical University of Denmark
We demonstrate a simple scheme for fabrication of microelectromagnets consisting of planar spiral coils semi-encapsulated in soft magnetic yokes using conventional microfabrication techniques. The microelectromagnets are suitable for applications operating at frequencies below 250 kHz. Conventional fabrication schemes for planar microelectromagnets typically rely on five mask steps. We allow the current to flow in the soft magnetic yoke and thereby two mask steps are eliminated. We have characterized the electromagnets electrically, the results agree well with theory, and the implications arising from current flowing in the magnetic yoke are discussed. We have integrated the microelectromagnets with microfluidic channels, and demonstrated separation of commercially available magnetic beads from a fluid in a microfluidic system, i.e. a lab-on-a-chip system.
Journal of Magnetism and Magnetic Materials, 2006, Vol 300, Issue 2, p. 418-426
Magnetic microsystems; Separation; Microelectromagnets; Magnetophoresis