Isolated and Collective Magnetic Phenomena in Metallic Nanocrystals and Their Superlattices

University Of Washington, Seattle WA

Investigators

Abstract

The research is directed at the synthesis, characterization and assembly of passivated, colloidal nanocrystals of metals into ordered superlattices with the fundamental goal of understanding the evolution of their static and dynamic magnetic behavior as a function of nanocrystal size and shape, superlattice dimensionality, organizational symmetry and interparticle interactions. The objective of the work is to use magnetometry methods to get a deeper understanding of the magnetic metrology of nanoscale structures. The study will provide fundamental mechanisms of magnetic reversal with emphasis on the role of finite size and interaction effects as well as the origin of dipolar ferromagnetism, in the absence of interparticle exchange interactions. The study emphasizes on the entropy-driven self-assembly and template-assisted crystallization processes for the synthesis of large-area (mm size) superlattices along with systematic structural and chemical characterization using electron and photon probes. Newly emerging MEMS based metrology methods and electron holography on the nanocrystal samples will be studied through collaborative work. The fundamental goal is a thorough understanding, prediction and control of cooperative magnetic behavior over different length scales and time signatures in artificially tailored solids. In addition, the work will provide solutions to fundamental questions associated with magnetic reversal. The research has broad technological implications for it will contribute to the development of the ultimate magnetic recording media, i.e. single-particle per bit recording as well as in MEMS technology.