Researchers at the University of Tübingen, Helmholtz-Zentrum Berlin, University of Nebraska and Trinity College have used a very thin layer of radicals, 10000 times thinner than a human hair, to coat a ferromagnetic material, polycrystalline cobalt, to change the magnetic properties of cobalt at the junction with the radicals.
Purely organic radicals are a family of molecules composed only of light elements, such as carbon, nitrogen, and oxygen. They are transparent, light, and flexible materials. They promise lower costs of production and sustainable, and recyclable chemistry. These radicals are organic molecules that carry an unpaired electron, i.e., they are materials with permanent magnetic properties. They must be used as a film in a device, i.e., the radical molecules cover a substrate such as a metal surface, forming a coating.
In the present work, Professor Casu from the University of Tübingen and her collaborators investigated the thin radical layer and the cobalt using X-ray photoelectron and X-ray absorption spectroscopy, techniques based on the interaction of electromagnetic radiation with matter in the X-ray range. The measurements were performed in the home lab in Tübingen, and at the BESSY synchrotron in Berlin.
The Casu Lab team found that a Blatter radical derivative thin layer can decrease the magnetic moment of the cobalt atoms because of the chemical bond that forms between the inorganic ferromagnetic and the organic magnet.
The novelty of the work is not only in the results but also in the methods that analyze in detail the electronic structure of the interface. This approach helps to screen organic/ferromagnetic interfaces for applications in spintronics in a simple way.
The molecules were synthesized by the Rajca lab, at the Department of Chemistry of the University of Nebraska. To get a deeper insight into the phenomena, Andrea Droghetti, Trinity College, Dublin, performed the theoretical calculations.