Credit: © 2009 APS

The gap remaining after carefully pulling a metallic wire beyond its breaking point can be controlled so as to be only a few atoms wide. These one-dimensional structures — known as break junctions — form the basis for atomic-scale studies on, for example, the electrical conductance of single molecules and spin-polarization. Intriguingly, despite reports on the formation of atomic chains of non-magnetic elements, such as gold and silver, in break junctions, the synthesis of chains of magnetic transition atoms has remained elusive.

Now, using first principles calculations, Alexander Thiess and colleagues1 at Forschungszentrum Jülich and Christian-Albrechts-Universität zu Kiel demonstrate that the formation of chains of magnetic elements in break junctions is impeded by magnetism. The researchers show that the formation of local magnetic moments suppresses the probability of chain formation in 3d, 4d, and 5d elements owing to 'softening' of the binding energy of the atomic chains.

These findings help provide a deeper understanding of the differences in the physical properties of bulk and nanometre-scale magnetic structures, and could also be useful in the development of devices for spintronics and quantum computing.