NSF award boosts UNL physicist's nanomaterials research

Released on 09/15/2015, at 9:06 AM
Office of University Communications
University of Nebraska–Lincoln
Lincoln, Neb., September 15th, 2015 —
Xiaoshan Xu (Craig Chandler/University Communications)
Xiaoshan Xu (Craig Chandler/University Communications)

A recently discovered nanomaterial with the rare quality of having both magnetic and electric polarizations may be the key to creating computers and other electronic devices that run at warp speed. A University of Nebraska-Lincoln physicist aims to learn how best to harness this power.

Xiaoshan Xu, assistant professor of physics, recently earned a five-year, $591,256 Faculty Early Career Development Program Award from the National Science Foundation to investigate a nanomaterial that could make electronics smaller, faster and more energy efficient. These prestigious grants, known as CAREER awards, support pre-tenure faculty who exemplify the role of teacher-scholars through outstanding research and education and the integration of the two.

"Conventional technology, like silicon technologies, is really hitting its limit," Xu said. "This work needs a new kind of material to break that barrier. People are attacking this problem from all directions."

Xu's weapon of choice is a hexagonal ferrite with multiferroic properties, which means the material contains both magnetic and electric polarizations. In today's electronics, processing and storing information require either constantly refreshing the status of semiconductor logic circuits or switching the polarization of magnetic materials. Both require an electric current, which uses energy and produces heat, limiting the efficiency and size of devices.

Theories predict that the hexagonal ferrite's electric field can be used to flip its magnetization without using heat-generating electricity. But scientists have yet to test these theories, and there's much to learn about harnessing this nanomaterial's properties.

While working at Oak Ridge National Laboratory, Xu led the effort that produced a pure, nano-thin version of the hexagonal ferrite and discovered its unique properties. Now at UNL, his goal is to better understand the fundamental mechanism underlying the coexistence of electric and magnetic properties inherent in the nanomaterial. Then, he'll investigate how to couple the two properties for use in devices.

Importantly, the material's multiferroic capability functions at significantly higher temperatures than similar useful materials discovered to date, but still requires a nippy minus 220 degrees Fahrenheit. With a better understanding of the ferrite's properties, Xu will investigate ways to raise its functional range to above room temperature and further expand its potential applications.

"There is a lot to learn from this material," Xu said. "It's very promising. It could make devices more energy efficient and compact. That's exactly what people are searching for."

Xu collaborates with colleagues in NSF-funded Materials Research and Engineering Center and the Nebraska Center for Materials and Nanoscience. 

"MRSEC brings together a lot of scientists with common interests," Xu said. "I don't do advanced theories, but through MRSEC, we have theorists who collaborate. That's a huge benefit."

Xu also is passionate about improving science, technology, engineering and mathematics, or STEM, education. The CAREER award allows him to seek additional opportunities to improve his own teaching and to work with colleagues to research new STEM educational methods. He also will continue to host high school students in his lab during summer programs and to mentor undergraduate and graduate students.

"A lot of students really struggle as they get into research," Xu said. "When you jump from learning from textbooks to creating knowledge, it's a huge gap. Many students get disappointed and give up. I really want to give them a better guide to get into research and maintain their interest."