The tremendous worldwide interest is stimulated by the fact that exploiting the electronic spin degree of freedom in solids could enable a revolutionary enhancement of the capabilities of electronic devices.
Tsymbal has been involved in the research on
spin electronics for the past 11 years. While working at the University of
Oxford he developed a novel theoretical approach to GMR in magnetic metallic
multilayers which emphasized the role of the electronic band structure as
the origin of this effect. His seminal GMR work was recognized by an invitation
by Professor Ehrenreich of Harvard University to write a review article for
the famous annual Solid State Physics series. Tsymbal’s article
“Perspectives of Giant Magnetoresistance” co-authored by Prof.
Pettifor, FRS appeared in 2001.
Since his arrival in Lincoln in 2002, Tsymbal has built a very productive
condensed matter theory group which currently includes two research assistant
professors, one visiting research associate and two graduate students. This
became possible due to the secured funding from the National Science Foundation,
Seagate Corporation, and the Nebraska Research Initiative, in addition to
the NSF Materials Research Science and Engineering Center (MRSEC) and the
W.M. Keck Foundation. Some of these funds were used to establish a high-power
multiprocessor computer cluster which is heavily used by Tsymbal’s group
and collaborators. The highlights of Tsymbal’s group research are four
publications in Physical Review Letters in 2005 devoted to (i) interlayer
exchange coupling across a tunnel barrier; (ii) ballistic anisotropic magnetoresistance;
(iii) giant electroresistance in ferroelectric tunnel junctions; (iv) tunneling
magnetoresistance in SrTiO3-based tunnel junctions. This research
work was recognized by numerous invitations of Tsymbal to international conferences
such as APS and MRS meetings and a Gordon Research Conference. Tsymbal’s
review article “Spin-dependent tunneling in magnetic tunnel junctions”
co-authored by Dr. Mryasov and Dr. LeClair and published in Journal of
Physics: Condensed Matter was highlighted in Top Paper 2003 Showcase.
Tsymbal is a coordinator of the MRSEC Interdisciplinary Research Group, one
of the two research groups within the NSF MRSEC established at UNL in 2002.
An important ingredient of Tsymbal’s research is collaboration with
his colleagues, both experimentalists and theorists. In particular, cooperation
with Prof. Jaswal strengthens the theory group due to his expertise in the
electronic band structure of solids. Another condensed matter theorist, Prof.
Belashchenko, who had made a major contribution to the group’s research
on spin-dependent tunneling, has started this academic year at the UNL Physics
and Astronomy Department in the new capacity of Assistant Professor. Partnership
with experimentalists, in particular, with Prof. Doudin has led to the understanding
of the magnetoresistance reversal in nanoscale magnetic tunnel junctions.
Collaboration with Prof. Dowben made it possible to elucidate the mechanism
of bonding of thiol-terminated molecules to cobalt and gold surfaces.
External collaborations of Tsymbal’s group include a number of universities
and research laboratories in United States and Europe. Also partnership with
industry, such as Seagate Corporation, plays an important role in Tsymbal’s
research activities. “Continuous technological effort to further miniaturize
electronic devices brings industry to the nanoscale world where properties
of materials are controlled by quantum phenomena. Further progress may only
be possible if these phenomena can be understood and fully exploited. This
puts unprecedented demands on theory and modeling”, says Tsymbal.
(Spring 2006)
