Spintronics breakthrough documented by UNL MRSEC team

A team at the University of Nebraska-Lincoln's Materials Research Science Engineering Center made a leap forward in modern spintronics, potentially revolutionizing information technology through reduced power consumption, faster processing speed and improved function compared to today's electronics.

Led by physicists in the UNL MRSEC, professors Christian Binek and Peter Dowben, together with theorist Kirill Belashchenko and collaborators published "Robust isothermal electric control of exchange bias at room temperature." The article appeared in the June 20 online edition of the journal Nature Materials, and will be published later in the print edition.

"The research team achieved a qualitative leap forward in modern spintronics," said Binek, associate professor of physics and astronomy. "Spintronics is a rapidly evolving research field that exploits the spin degree of freedom of electrons to create an advanced generation of electronic devices. The spin of an electron is a purely quantum mechanical property but can to some extent be pictured in analogy to the classical angular momentum of a spinning top."

Binek said it is this spin degree of freedom that is responsible for the magnetic moment of an electron allowing it to interact with a magnetic field similar to the interaction of a compass needle aligning in Earth's magnetic field. The spin provides an "experimental handle" in addition to the electron charge to control electrons, and thus making spintronic devices feasible.

He said spintronic devices could revolutionize information technology through reduced power consumption, enhanced processing speed, integration density and functionality when compared to present day complementary metal-oxide-semiconductor electronics.

In their experiments the researchers grew a ferromagnetic film on top of chromia, an exotic magnetoelectric material that reacts with excess magnetization when exposed to an electric field. Using specific theoretical insights the researchers realized pure voltage-control of the magnetic state of the ferromagnetic film. Achieving such control at room temperature resembles a significant breakthrough in this research and promises a new route toward voltage-controlled spintronics and electrically controlled magnetism, Binek said.

Under the guidance of Binek, Dowben and Belashchenko, important hands-on contributions came from UNL graduate students Xi He, Yi Wang and UNL postdoctoral researcher Ning Wu, supported by Anthony Caruso from the University of Missouri-Kansas City and Elio Vescovo from Brookhaven National Laboratory.

The paper is published online at www.nature.com/nmat/journal/vaop/ncurrent/abs/nmat2785.html. The National Science Foundation supports this research.

WRITERS: Christian Binek, with Kelly Bartling, University Communications