23-Sep-2016 - Eberhard-Karls-Universität Tübingen

Defects at the spinterface disrupt transmission

Researchers put metal-oxides and organic magnets together; applications for electronics in sight

Magnets made of organic materials have a number of advantages over the classic metal or alloy magnets. They are chemically more flexible, cheaper to make, and can be better adapted to various purposes and varying designs. In practice, researchers want to apply both types of magnets in electronics – in spintronic elements, which transport information not by electrical load but via the spin of the component molecules. This intrinsic angular momentum is a typical characteristic of particles, such as electrons. Reza Kakavandi, Professor Thomas Chassé and Dr. Benedetta Casu of the Institute of Physical Chemistry at the University of Tübingen have investigated just such a magnetic interface between the titanium oxide crystals in rutile form and a purely organic magnet. They found that the transition area where the materials met was highly sensitive to minimal defects in the surfaces.


Purely organic radicals are composed of light elements such as carbon, nitrogen and oxygen, and usually have one unpaired electron, which creates permanent magnetic momentum. “They are interesting in a whole lot of applications;” says Benedetta Casu, “They can be used particularly in storage elements, batteries, sensors and for biomedical applications. They could also be used in the construction of a quantum computer.” The Tübingen researchers investigated the interface between a single rutile crystal and an organic radical using a very high resolution x-ray spectroscopy procedure combined with theoretical calculations by Dr. Arrigo Calzolari of the Istituto Nanoscienze in Modena, Italy. The researchers call this link between conventional and organic magnets the “spinterface” because it combines the ideas of “spin” and “interface”.

“In this experiment, organic radicals are held in place physically, and the magnetic momentum was kept between the different materials,” says Benedetta Casu. She says it worked well. But, she says, the situation changed completely when there was a tiny defect on the relevant surface of the rutile – i.e., if the crystal surfaces were not ideally ordered. “In that case, the organic radical bonded chemically with the reactive point of the defect, wiping out the magnetic momentum,” Casu explains.

This approach with the combination of x-ray spectroscopy and theoretical calculations proved to be very useful in helping the researchers to understand the mechanisms at this complex interface, according to Casu. The researchers needed to describe both the electrical charges involved as well as the spin. For the first time it became clear what important influences arise from surface defects at one of these spinterfaces. “It’s a key result, equally valid in chemistry and in physics as well as for materials sciences,” says Casu.

Facts, background information, dossiers

  • interfaces
  • organic material magnets
  • metal oxides

More about Universität Tübingen

  • News

    Tackling the collateral damage from antibiotics

    Antibiotics help us to treat bacterial infections and save millions of lives each year. But they can also harm the helpful microbes residing in our gut, weakening one of our body’s first lines of defence against pathogens and compromising the multiple beneficial effects our microbiota has f ... more

    Fungus produces active agent in a medicinal herb

    Tatarinow's aster is used in traditional Chinese medicine to treat a number of ailments; the plant contains an active ingredient known as astin – and it is this agent which cancer researchers are now investigating. However, the plant does not produce the astins itself, as was assumed for a ... more

    Making cancer stem cells visible to the immune system

    Leukemia stem cells protect themselves against the immune defense by suppressing a target molecule for killer cells. This protective mechanism can be tricked with drugs. In the journal "Nature", scientists from Basel, Tübingen and Heidelberg describe the new therapeutic approaches that can ... more

  • q&more articles

    Putting Pressure on Pharmaceuticals

    As a general rule, the pharmaceuticals industry develops new drugs by applying a complex procedure of formulation utilising excipients suitable for the final drug dosage form. Such development processes are carried out by the companies’ technical departments and in many cases result in solu ... more

    Staying power

    Geoscientists, biologists and chemists at the University of Tübingen are working in collaboration with IFAM (Fraunhofer Institute for Manufacturing Technology and Advanced Materials in Bremen, Germany) to uncover the workings of insect surface adhesion. The goal of this project is the synth ... more

  • Authors

    Prof. Dr. Michael Lämmerhofer

    Michael Lämmerhofer studied pharmacy at the University of Graz, receiving his doctorate in pharmaceutical chemistry in 1996. This was followed by a move to the University of Vienna, where, with the exception of a one-year postdoc at the University of Berkeley (from 1999 to 2000), his positi ... more

    Heike Gerhardt

    Heike Gerhardt studied chemistry at the universities of Tübingen and Vienna, already choosing to specialize in analysis during her master’s degree at the University of Vienna. She has worked at the University of Tübingen under Prof. Lämmerhofer since 2012: with her doctoral research work ne ... more

    Prof. Dr. Martin A. Wahl

    studied pharmacy at the University of Tübingen and was awarded his doctorate in 1984. Following a one-year period of research at the Karolinska Institutet in Stockholm, he completed his habilitation in pharmacology and toxicology in 1995. In 1998, he moved to the University of Tübingen’s Ph ... more

q&more – the networking platform for quality excellence in lab and process

The q&more concept is to increase the visibility of recent research and innovative solutions, and support the exchange of knowledge. In the broad spectrum of subjects covered, the focus is on achieving maximum quality in highly innovative sectors. As a modern knowledge platform, q&more offers market participants one-of-a-kind networking opportunities. Cutting-edge research is presented by authors of international repute. Attractively presented in a high-quality context, and published in German and English, the original articles introduce new concepts and highlight unconventional solution strategies.

> more about q&more

q&more is supported by: