Researchers at the National Institute of Standards and Technology have made the first confirmed “spintronic” device incorporating organic molecules, a potentially superior approach for innovative electronics that rely on the spin, and associated magnetic orientation, of electrons. The physicists created a nanoscale test structure to obtain clear evidence of the presence and action of specific molecules and magnetic switching behavior.
Spintronic devices usually are made of inorganic materials. The use of organic molecules may be preferable, because electron spins can be preserved for longer time periods and distances, and because these molecules can be easily manipulated and self-assembled. However, until now, there has been no experimental confirmation of the presence of molecules in a spintronic structure. The new NIST results are expected to assist in the development of practical molecular spintronic devices.
The experiments, described in the October 9 issue of Applied Physics Letters, used a specially designed nanoscale “pore” in a silicon wafer. A one-molecule-thick layer of self-assembled molecules containing carbon, hydrogen and sulfur was sandwiched in the pore, between nickel and cobalt electrodes. The researchers applied an electric current to the device and measured the voltage levels produced as electrons “tunneled” through the molecules from the cobalt to the nickel electrodes. (Tunneling, observed only at nanometer and atomic dimensions, occurs when electrons exhibit wave-like properties, which permit them to penetrate barriers.)