Stray Magnetic Field Variations and Micromagnetic Simulations: Models for NiFe Disks Used for Microparticle Trapping.

Patterned micro-scale thin-film magnetic structures, in conjunction with weak (~few tens of Oe) applied magnetic fields, can create energy landscapes capable of trapping and transporting fluid-borne magnetic microparticles. These energy landscapes arise from magnetic field magnitude variations that arise in the vicinity of the magnetic structures. In this study, we examine means of calculating magnetic fields in the local vicinity of permalloy (NiFe) microdisks in weak (~tens of Oe) external magnetic fields.