Size and Interface Dependent Magnetic Properties of Encapsulated Metal Clusters

Abstract

The properties of magnetic nanoparticles is an area of current active interest with many problems of fundamental importance [1–4]. The nanoscale places particles at the single domain size where the coercivity can have a maximum or below this size where the particles eventually become superparamagnetic with no coercivity [5]. The density of states of various excitations in nanoparticles is affected by size through coarsening and/or introduction of a finite wavelength cut off. And, perhaps most importantly, nanoparticles have a large fraction of surface atoms which may have properties distinctly different than those in the bulk. Moreover, the exposed nature of the surface makes it susceptible to interfacial materials which might modify the properties of the surface atoms.