Theory of Superconducting and Electromagnetic Properties of Some Nanostructured Materials David Stro

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Theory of Superconducting and Electromagnetic
Properties of Some Nanostructured MaterialsDavid
Stroud, Ohio State UniversityNSF DMR-0413395

• Research Highlight Forces in
  Electrorheological (ER) Fluids
• An ER fluid is a material whose viscosity
  (resistance to flow) can be changed by an
  electric field (e. g. with a battery).
• They usually consist of suspensions of
  dielectric spheres in a host made of another
  insulator.
• If an electric field is applied, the spheres line
  up, making the suspension more viscous (instead
  of behaving like water, it becomes more like
  honey).
• In our method, we connect the forces to the
  optical properties of the spheres.

E
SrTi03
Silicone oil
Two strontium titanate spheres (diameter 6.3 mm)
in silicone oil are strongly attracted when
electric field E 71 volts/mm is applied.
Force is strongly attractive and depends on
frequency. Spheres separated by only 0.1-0.3mm
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Theory of Superconducting and Electromagnetic
Properties of Some Nanostructured MaterialsDavid
Stroud, Ohio State UniversityNSF DMR-0413395

• Contributions to Education
• Six grad students (Kwangmoo Kim, Daniel
  Valdez-Balderas, Ivan Tornes, Kohjiro Kobayashi,
  Vishwesha Guttal, Rakesh Tiwari), one postdoc
  (Sung Yong Park), one undergrad REU student
  (Bryan Chen) and another undergrad (Stefan Natu)
  have contributed to work on this grant. Ivan
  Tornes is now a staff scientist at Battelle Park
  has a postdoc at Northwestern.
• I have discussed ER fluids in my graduate
  electromagnetism course, including research
  findings from this work.

• Some potential applications
• Change in viscosity with applied electric field
  gives a motor oil with controllable thickness
  (already used in car brakes).
• 2. At optical frequencies, if the spheres are
  small and metallic, rather than large and
  non-metallic, the same principle can be used to
  calculate the force between the spheres induced
  by a strong light beam.
• Publications
• Kwangmoo Kim, David Stroud,
• X. Li, D. J. Bergman, Phys. Rev.
• E71, 031503 (2005) Li, Bergman and Stroud,
  Europhys. Lett. 69, 1010 (2005).