Paramagnetic and superparamagnetic silicon nanocomposites

Abstract

In this chapter the paramagnetic properties of nanostructured silicon are outlined and furthermore the magnetic properties of a composite material consisting of porous silicon with infiltrated superparamagnetic iron oxide nanoparticles are discussed. The magnetic behavior of the system depends on the nanoparticle size as well as on the magnetic coupling between them. Both influence the so-called blocking temperature, the transition between superparamagnetic behavior and blocked state. A particle size-related assessment shows that the blocking temperature increases with increasing particle size if the distances between the particles are equal. The blocking temperature can be decreased by weakening the magnetic interaction between the particles. Due to the good biocompatibility of both porous silicon and iron oxide nanoparticles, the composite system is of interest for biomedical applications in the fields of therapy and diagnosis.