Magnetic oxygen behaves like a transition metal
Researchers
from the FOM Foundation, the University of Groningen and Radboud University
Nijmegen have discovered a new type of magnetism, based on the relatively light
element oxygen. This offers the possibility of designing new magnets based on
oxygen. This could have consequences within the discipline of spintronics, as the
light elements offer particular advantages. Furthermore, in the long-term this
could prove to be the basis for a magnetic bit for use in fast and energy
efficient computers. The results were published on 1 June in the renowned
journal Physical Review Letters, with a recommendation from the editor.
Crystalsof caesium superoxide (CsO2) have been shown to have specialmagnetic properties. Magnetic materials have unpaired electrons. That usuallyonly occurs in heavier elements such as transition metals (for example iron) orrare earth metals (for example neodymium). Now it has been discovered that therelatively light element oxygen in caesium superoxide (CsO2) canalso behave as a transition metal. The superoxide has an unpaired electron andis therefore magnetic. The magnetic properties of superoxide had scarcely beenstudied up until now.
Theorbits of the free electrons in these crystals were found to be highly ordered.This so-called orbital ordering had so far only been observed in transitionmetal compounds. However, the research team used a combination of theory andexperiments to demonstrate that it can also occur in the superoxide. Theylinked the magnetic moments of the unpaired electrons (the so-called spins) of CsO2 antiparallel to aone-dimensional spin chain. This means that the magnetic interactions betweenneighbouring molecules only occur in a single direction of the crystalstructure. The mechanism that causes the spin chain is based on the molecularorbits the unpaired electrons are in.
Reference
AntiferromagneticS = ½ Spin Chain Driven by p-Orbital Ordering in CsO2 , Syarif Riyadi, Baomin Zhang, Robert A. deGroot, Antonio Caretta, Paul H.M. van Loosdrecht, Thomas T.M. Palstra, and GraemeR. Blake, http://link.aps.org/doi/10.1103/PhysRevLett.108.217206(published on 25 May online).
You can contact the researcher, Dr Graeme Blake, +31 (0)50 363 44 14. See also the article on Science Linx.