Collective Effects in Assemblies of Magnetic Nanaparticles

Abstract

Abstract The study of ferromagnetic nanoparticles is of broad scientific interest, crossing the traditional boundaries between physics, chemistry, and biology. Indeed, recent research can be found on magnetic nanoparticle assemblies in all of these fields. While we do not aim to provide an exhaustive study on the science of magnetic nanoparticles, we will aim to give a brief introduction to the physics of this class of material. In particular, we will outline some of the recent scientific research on these systems including both theoretical and experimental aspects. After providing a broad and general overview to theoretical aspects to the study of magnetic nanoparticle assemblies, including both equilibrium and dynamical considerations, we will discuss some of the principal experimental techniques which have been employed in the study of their collective magnetic properties. We pay particular attention to the interplay between the intrinsic properties of the material and the size, shape, temperature, and dipolar interactions, which define the global state of the nanoparticle array. We further introduce and discuss experimental methods used to characterize magnetic nanoparticle assemblies, providing a brief overview of the methodology and select some representative results to demonstrate the type of information that can be obtained with each technique under varying experimental conditions.