Nano-magnetism and high-density magnetic memory

1
Nano-magnetism and high-density magnetic
memory Vitali Metlushko, Department of Electrical
Computer Engineering, UIC Prime Grant
Support NSF ECS grant ECS-0202780, Antidot and
Ring Arrays for Magnetic Storage Applications and
  NSF NIRT grant DMR-0210519 Formation and
Properties of Spin-Polarized Quantum Dots in
Magnetic Semiconductors by Controlled Variation
of Magnetic Fields on the Nanoscale, B. Janko
(P.I.), J. K. Furdyna (co-P.I.), M. Dobrowolska
(co-P.I.), University of Notre Dame is leading
organization, A. M. Chang (Purdue) and V.
Metlushko, (UIC)
Problem Statement and Motivation
The field of nanoelectronics is overwhelmingly
dedicated to the exploitation of the behavior of
electrons in electric fields. Materials employed
are nearly always semiconductor-based, such as Si
or GaAs, and other related dielectric and
conducting materials. An emerging basis for
nanoelectronic systems is that of magnetic
materials. In the form of magnetic random access
memories (MRAM), nanoscale magnetic structures
offer fascinating opportunities for the
development of low-power and nonvolatile memory
elements.
Key Achievements and Future Goals
Technical Approach
In past few years, the interest in nano-magnetism
has encreased rapidly because they offer
potential application in MRAM. Modern fabrication
techniques allow us to place the magnetic
elements so close together that element-element
interactions compete with single-element energies
and can lead to totally different switching
dynamics. To visualize the magnetization
reversal process in individual nano-magnets as
well as in high-density arrays, Metlushko and his
co-authors employed several different imaging
techniques- magnetic force microscopy (MFM),
scanning Hall microscopy, magneto-optical (MO)
microscopy, SEMPA and Lorentz microscopy (LM).

• This project has led to collaboration with MSD
  and APS ANL, Los Alamos NL, Katholieke
  Univesiteit Leuven, Belgium, University of Notre
  Dame, NIST, Universita di Ferrara, Italy,
  Inter-University Micro-Electronics Center (IMEC),
  Belgium, Cornell University, McGill University
  and University of Alberta, Canada
• During the past 3 years this NSF-supported work
  resulted in 21 articles in refereed journals
  already published and 10 invited talks in the US,
  Europe and Japan
• .

2
Nanocrystalline Carbide Derived Carbon for
Tribological Applications Investigators Michael
McNallan, Civil and Materials Engineering, UIC
Ali Erdemir, Argonne National Laboratory Prime
Grant Support U.S. Department of Energy
Problem Statement and Motivation
max. safe temperature

• Mechanical Seals and bearings fail due to
  frictional heating and wear
• Materials used are hard ceramics, such as SiC or
  WC
• Friction can be reduced by coating with carbon
  as graphite or diamond
• Graphitic coatings are not wear resistant
• Diamond coatings are wear resistant, but fail by
  spallation or delamination from the underlying
  ceramic

SiC-SiC
SiC-CDC
Pump seal face temperature during dry running at
4000 rpm With and without CDC coating
Key Achievements and Future Goals
Technical Approach

• Produce a low friction carbon layer by chemical
  conversion of the surface of the carbide
• SiC(s) 2Cl2(g) ? SiCl4(g) C(s)
• At temperatures lt 1000oC, carbon cannot relax
  into equilibrium graphitic state and remains as
  Carbide Derived Carbon (CDC)
• CDC coating contains nano-porous amorphous C,
  fullerenes, and nanocrystalline diamond
• CDC is low friction, wear resistant, and
  resistant to spallation and delamination

• CDC has been produced in the laboratory
• Its structure and conversion kinetics have been
  characterized
• Tribological performance was verified in
  laboratory and industrial scale pump tests with
  water
• CDC was patented and selected for an RD 100
  Award in 2003
• CDC was Licensed to Carbide Derivative
  Technologies, Inc.in 2006
• Scale up to industrial production rates,
  characterization of process reliability and
  testing in specific industrial environments is
  the next goal.

3
Carbon Nanopipes for Nanofluidic Devices
Investigators C. M. Megaridis, Mechanical and
Industrial Eng., UIC Y. Gogotsi, J.C. Bradley,
Drexel Univ. H. Bau, Univ. Pennsylvania A.
Yarin, Technion-Israel Prime Grant Support
National Science Foundation
Problem Statement and Motivation

• Investigate the physical and chemical properties
  of aqueous fluids contained in multiwall carbon
  nanotubes
• Determine the continuum limit for fluid behavior
  under extreme confinement
• Provide experimental data for parallel modeling
  efforts
• Evaluate the feasibility of fabricating devices
  using carbon nanotubes as building blocks

Key Achievements and Future Goals
Technical Approach

• Multiwall carbon nanotubes filled by
  high-pressure high-temperature processing in
  autoclaves
• Nanotube diameter in the range 5nm-200nm, and
  lengths 500nm-10µm
• Gas/liquid interfaces used as markers of fluid
  transport
• High-resolution electron microscopy and chemical
  analysis techniques used to resolve behavior of
  fluids stimulated thermally in the electron
  microscope
• Model simulations used to interpret experimental
  observations

• Gas/Liquid interfaces in carbon nanotubes
  resemble interfaces in macroscopic capillaries
  when nanotube diameter is above 10nm
• Non-continuum behavior observed in nanotubes
  with diameter below 10nm
• Wettability of carbon walls by water observed
  important property for adsorption applications
• Future applications include drug delivery
  systems, lab-on-a-chip manufacturing,
  electrochemical cells, etc.