When scientists and engineers discover new ways to optimize existing
materials, it paves the way for innovations that make everything from
our phones and computers to our medical equipment smaller, faster, and
more efficient.
According to research published today by Nature Journal
NPG Asia Materials,
a group of researchers — led by Edwin Fohtung, an associate professor
of materials science and engineering at Rensselaer Polytechnic Institute
— have found a new way to optimize nickel by unlocking properties that
could enable numerous applications, from biosensors to quantum
computing.
They demonstrated that when nickel is made into extremely small,
single-crystal nanowires and subjected to mechanical energy, a huge
magnetic field is produced, a phenomenon known as giant
magnetostriction.
Inversely, if a magnetic field is applied to the material, then the
atoms within will change shape. This displacement could be exploited to
harvest energy. That characteristic, Fohtung said, is useful for data
storage and data harvesting, even biosensors. Though nickel is a common
material, its promise in these areas wasn’t previously known.
“Imagine building a system with large areas of nanowires. You could
put it in an external magnetic field and it would harvest a very huge
amount of mechanical energy, but it would be extremely small,” Fohtung
said.
The researchers uncovered this unique property through a technique
called lensless microscopy, in which a synchrotron is used to gather
diffraction data. That data is then plugged into computer algorithms to
produce 3D images of electronic density and atomic displacement.
Using a big data approach, Fohtung said, this technique can produce
better images than traditional microscopes, giving researchers more
information. It combines computational and experimental physics with
materials science — an intersection of his multiple areas of expertise.
“This approach is capable of seeing extremely small objects and
discovering things we never thought existed about these materials and
their uses,” Fohtung said. “If you use lenses, there’s a limit to what
you can see. It’s determined by the size of your lens, the nature of
your lens, the curvature of your lens. Without lenses, our resolution is
limited by just the wavelength of the radiation.”
Fohtung used this same technique to show that barium hexaferrite — a
universal and abundant material often used in tapes, CDs, and computer
components — has spontaneous magnetic and electric polarization
simultaneously that increases and decreases when exposed to an electric
field. The property, known as ferroelectricity, is useful for
fast-writing, power-saving, and data storage. Those findings were
recently published in
Physical Review B.
Fohtung believes that the lensless approach to studying substances
will allow researchers to learn even more about solid state materials,
like those used in technological devices. It may even enable deeper
understanding of human tissue and cells, which could be viewed in a more
natural habitat using this technique.
“What excites me so much about it is the potential for the future.
There are so many existing materials that we are just not able to
understand the potential applications,” Fohtung said.
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Fohtung worked with researchers from Los Alamos National Laboratory,
New Mexico State University, and Argonne National Laboratory on both
publications.
https://www.eurekalert.org/pub_releases/2019-10/rpi-bdt101619.php
