Oxygen loses its magnetism under pressure

A solid-state transformation in oxygen that physicists had long thought might occur has finally been observed. Oxygen is a highly magnetic molecular solid at low temperatures, but physicists had for years speculated that its magnetism disappears at high pressures. Now Igor Goncharenko from the Laboratoire Léon Brillouin (LLB) in Saclay, near Paris, has found that oxygen becomes non-magnetic at about 80,000 times atmospheric pressure. The work could help astronomers to understand the interiors of giant planets like Jupiter and Saturn, which contain oxygen and other insulating solids like nitrogen and hydrogen (I Goncharenko 2005 Phys. Rev. Lett. 94 205701).