Properties of Some Nanostructured Materials

winkwellmadeUrban and Civil

Nov 15, 2013 (3 years and 9 months ago)

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Theory of Superconducting and Electromagnetic
Properties of Some Nanostructured Materials

David Stroud, Ohio State University

NSF DMR04
-
13395



Research highlight
:
nanostructured high
-
temperature superconductors.



A high
-
temperature superconductor carries electrical current with
no
resistance
up to about half room temperature.



Recent studies show that they are actually
granular,

not smooth.


We have treated electrons in this granular superconductor by computer
simulations. We find that the superconductor has very different properties in
the two granular regions (see picture at lower right).











Superconducting
layer looks like
random grains of
``good’’ (beta)
material scattered in
a ``fairly good’’
(alpha) host (left).
Microscopic spectra
can be calculated in
both regions versus
temperature (right).

D. Valdez
-
Balderas, D. Stroud, Phys. Rev. B (in press).

(Sketch of granular superconductor)

Theory of Superconducting and Electromagnetic Properties of Some
Nanostructured Materials

David Stroud, Ohio State University

NSF DMR04
-
13395





Contributions to Education:






Six grad students

(Daniel Valdez
-
Balderas, Ivan
Tornes, Kwangmoo Kim, Kohjiro Kobayashi,
Rakesh Tiwari, and Vishwesha Guttal),
one postdoc

(Sung Yong Park),

two undergrad students

[Bryan
Chen (Harvard U.), and Stefan Natu (Ohio
Wesleyan)] have contributed to work done under
this grant. Ivan Tornes is now a staff scientist at
Battelle; Park has a postdoc at Northwestern.



I have discussed superconductivity and optical
properties in my graduate courses, including
discussion of pattern formation and disorder in
superconductors. I am mentoring a high school
student on a project in quantum computing.













Above: examples of
inhomogeneous

superconducting patterns

calculated from
simple models [see Valdez
-
Balderas and

Stroud, Phys. Rev. B72, 214501 (2005)].

This ``granularity’’ greatly influences

high
-
Tc materials when they are used as
electromagnetic filters

[Kwangmoo Kim
and D. Stroud, submitted to J. Appl.
Phys.]; may even improve properties.