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Posted: Jan 21, 2014
Engineering novel magnetic and electronic phases in ultra-thin films
(Nanowerk News) Physicists at the University of Arkansas and their collaborators have engineered novel magnetic and electronic phases in the ultra-thin films of in a specific electronic magnetic material, opening the door for researchers to design new classes of material for the next generation of electronic and other devices.
“Pressure is an absolutely fantastic tool to change the properties of any compound,” said Jak Chakhalian, professor of physics at the U of A. “But how do you apply pressure to something that is nanoscale? We’ve finally found a way to systematically exert ‘pressure’ on this thin nanomaterial, which has only a few atomic layers, to enable new electronic and magnetic phases.”
Chakhalian and his former doctoral student Jian Liu found a way to apply pressure to the magnetic material by varying the distances between atoms with a crystal lattice substrate. The compression forced the material into new phases, with intriguing properties not attainable in the larger crystals. Thus, the physicists developed a tool that allows them to control and engineer the novel behavior of the nanomaterial on an atomic scale, Chakhalian said.
“In general, nature is remarkably scalable,” he said. “If a material is a conductor of electricity, it doesn’t matter what size it is; it will conduct electricity. The naïve expectation in the 1990s was that anything we shrunk down to nano size would act profoundly differently, and we did develop many remarkable tools that were capable of shrinking them down to hundreds, and recently, tens of nanometers. But it turned out we didn’t go far enough. As we know now, we really need to go one magnitude lower: the atomic scale. Then these things get really strange.
“In order to find out the fundamental reason for how material properties emerge, for example why a material conducts electricity or why it is magnetic, I need to go smaller and smaller,” he said.
That’s why Chakhalian and his researchers are exploring the behavior of materials at the size several angstroms per layer, a unit equal to one-hundred millions of a centimeter.
This is the third paper produced by Chakhalian’s research group that appeared in a Nature publication in 2013.