Multilayered Magnetic Nanodisks for Biosensing

We present the design and fabrication of a new type of magnetic nanoparticles for biosensing applications. In these nanoparticles, two key magnetic requirements, a high saturation magnetic moment and a near zero remanent moment are achieved by a non-superparamagnetic mechanism, the magnetostatic interlayer coupling between two magnetic layers. A pillar-template-based synthesis is employed to produce large quantities of these multilayered magnetic nanodisks. These nanoparticles can fill the superparamagnetic nanoparticle size gap, from 20 nm to 100 nm. Each nanoparticle is detectable by a magnetoresistive sensor which is highly desirable for biosensing applications.