“Self-organization” of nano-devices: Magnetic molecules (green) arrange on a carbon nanotube (black) to build an electronic component (Photo: C. Grupe, KIT). |
Magnetic
storage media such as hard drives have revolutionized the handling of
information: We are used to dealing with huge quantities of magnetically
stored data while relying on highly sensitive electronic components.
And hope to further increase data capacities through ever smaller
components. Together with experts from Grenoble and Strasbourg,
researchers of KIT’s Institute of Nanotechnology (INT) have developed a
nano-component based on a mechanism observed in nature.
What
if the very tininess of a component prevented one from designing the
necessary tools for its manufacture? One possibility could be to “teach”
the individual parts to self-assemble into the desired product. For
fabrication of an electronic nano-device, a team of INT researchers
headed by Mario Ruben adopted a trick from nature: Synthetic adhesives
were applied to magnetic molecules in such a way that the latter docked
on to the proper positions on a nanotube without any intervention. In
nature, green leaves grow through a similar self-organizing process
without any impetus from subordinate mechanisms. The adoption of such
principles to the manufacture of electronic components is a paradigm
shift, a novelty.
The
nano-switch was developed by a European team of scientists from Centre
National de la Recherche Scientifique (CNRS) in Grenoble, Institut de
Physique et Chimie des Matériaux at the University of Strasbourg, and
KIT’s INT. It is one of the invention’s particular features that, unlike
the conventional electronic components, the new component does not
consist of materials such as metals, alloys or oxides but entirely of
soft materials such as carbon nanotubes and molecules.
Terbium,
the only magnetic metal atom that is used in the device, is embedded in
organic material. Terbium reacts highly sensitively to external
magnetic fields. Information as to how this atom aligns along such
magnetic fields is efficiently passed on to the current flowing through
the nanotube. The Grenoble CNRS research group headed by Dr. Wolfgang
Wernsdorfer succeeded in electrically reading out the magnetism in the
environment of the nano-component. The demonstrated possibility of
addressing electrically single magnetic molecules opens a completely new
world to spintronics, where memory, logic and possibly quantum logic
may be integrated.
The
function of the spintronic nano-device is described in the July issue
of Nature Materials (DOI number: 10.1038/Nmat3050) for low temperatures
of approximately one degree Kelvin, which is -272 degrees Celsius.
Efforts are taken by the team of researchers to further increase the
component’s working temperature in the near future.