Buckyballs turn on copper’s magnetism

A new recipe for magnetism calls for an infusion of nano-sized soccer balls.

When exposed to sheets of carbon-atom cages called buckyballs, copper and manganese become permanent magnets, researchers report in the Aug. 6 Nature. The technique could enable engineers to expand the roster of metals for magnet-based technology, including computer memory and medical imaging.

Previously, iron, cobalt and nickel were the only elements to be room-temperature ferromagnets, materials that retain magnetism after exposure to a magnetic field. Despite bookending those three elements on the periodic table, copper and manganese ordinarily don’t support the coordinated electron spin that’s necessary for ferromagnetism.

Oscar Céspedes, a condensed matter physicist at the University of Leeds in England, and colleagues tried to remedy that by stacking metal films and sheets of buckyballs, which tend to steal electrons from metals. This subatomic robbery changed the behavior of the metals’ remaining electrons. After exposure to a magnetic field, the metal-buckyball layer cakes exhibited about 3 percent of the magnetic strength of iron.

Céspedes says his team is trying out other metals and working to enhance the synthetic magnets’ strength for use in commercial applications.