Project 1: Spin Clusters and Nanomagnetic Information Processing
Professors D. J. Sellmyer (Coordinator), R. D. Kirby, S.-H. Liou, R. Skomski; Drs. Y. Xu, K. Sorge, A. Kashyap; GRA L. Gao, J. G. Long
 A high resolution transmission electron microscopy (TEM) image from 5.6 nm Co clusters produced in our cluster deposition system. [Note higher resolution image is insert at lower right.] |
The aims: - synthesize spin clusters and nanoscale patterned thin-film structures - understand their magnetic interactions and properties. This work is relevant to two frontier areas of advanced research: fundamental physics limits on density of data storage and spin-logic structures for information processing. We are addressing these topics by fabricating and studying spin clusters and arrays of nanoscale magnetic ‘dots’ with interactions of controlled strength. |
The theme of this project is the study of exchange
and magnetostatic interactions between spin clusters or patterned dots in nanostructures.
Understanding these interactions is a fundamental problem in nanoscale magnetism
and spin electronics and is of technological importance in magnetic recording
media, magnetoresistive sensors, and permanent-magnet materials.
Since nonlocal, nonlinear, and nonequilibrium effects play important roles in
nanostructures, the atomic origin of their magnetism requires relativistic (i.e.,
spin-dependent) quantum-mechanical solutions for very complex interfaces and
boundaries. This project brings a powerful combination of theoretical and experimental
expertise to bear on fundamental quantum and electronic-structure aspects of
nanomagnets and magnetic interfaces, nanofabrication issues, and basic exchange
and magneto-static interactions.
In the last few years interest in cluster science has grown enormously, with
increasing attention devoted to the effect of nano-size confinement on the physical
properties of clusters and the potential uses of clusters in the nanoscale engineering
of materials with very specific properties. For most technological applications,
the properties of embedded clusters are more important than those of free ones.
Nanophase materials, assembled using nanoclusters as building blocks, can be
synthesized to have a wide variety of controlled optical, electronic, magnetic,
and chemical properties. An important goal of this research is to employ a new
multiple-source cluster deposition system to create spin clusters, investigate
spin interactions in cluster-assembled materials, and investigate the feasibility
of such materials for extremely high-density magnetic recording.
Patterned magnetic nanostructures such as nanodot arrays, patterned recording
media, arrays produced by laser-interference lithography, and electrodeposited
nanowires exhibit a rich physics, from nanoscale quantum-mechanical effects
to macroscopic interactions.
1.1. Spin Clusters and Interactions
1.2. Nanomagnetic Spin-Logic Systems