Terahertz spectroscopy provides basis for advanced
nanoelectronics
(July 7, 2015) The
forward-looking technology of spintronics now has a new, highly effective
investigative instrument: German physicists from Mainz and Berlin have
successfully employed ultrafast terahertz spectroscopy to determine the basic
properties of spintronics components. "We thus now have direct access to
the most fundamental elements of magnetotransport," said Professor Mathias
Kläui of the Institute of Physics at Johannes Gutenberg University Mainz (JGU).
Spintronics uses not only the charge of electrons for the purpose of
information processing but also their spin, or in other words, their magnetic
moment. The principles of spintronics are already being employed in hard drive
reading heads and sensors, such as those used by the automotive industry, and
offer enormous potential with regard to the development of non-volatile memory
systems.
The basis of many spintronics-related applications is the
giant magnetoresistance effect or GMR, which was discovered in the 1980s by
Albert Fert and Peter Grünberg, who were awarded the Nobel Prize in Physics in
2007 as a result. The GMR effect works like a kind of magnetic sensor, the resistance
of which changes depending on the magnetic orientation of the individual thin
films in the composite material. This leads to a certain scattering of
electrons, the effect of which becomes apparent as resistance. However, it has
not proved possible to date to precisely measure this effect with the
experimental methods available. The main problem was the extremely short
duration of these effects. The electron scattering events occur on a time scale
of less than 100 femtoseconds, a femtosecond being one quadrillionth of a
second.