Letters to Nature

Nature 393, 767-769 (25 June 1998) | doi:10.1038/31656; Received 3 July 1997; Accepted 16 April 1998

Superconductivity in oxygen

K. Shimizu1,2, K. Suhara1, M. Ikumo1, M. I. Eremets2 & K. Amaya1,2,3

  1. Department of Material Physics, Faculty of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
  2. CREST of Japan Science and Technology Corporation, Kawaguchi, Saitama 332-0012, Japan
  3. Advanced Science Research Center, Japan Atomic Energy Research Institute, Naka, Ibaraki 319-1195, Japan

Correspondence to: K. Shimizu1,2 Correspondence and requests for materials should be addressed to K.S. (e-mail: Email: kshimizu@mp.es.osaka-u.ac.jp).

Among the simple diatomic molecules, oxygen is of particular interest because it shows magnetism at low temperatures. Moreover, at pressures exceeding 95 GPa (approx0.95 Mbar), solid molecular oxygen becomes metallic, accompanied by a structural transition1. The metallization process is characterized by an increase in optical reflectivity2, and a change in the slope of the resistance–temperature curve3. Here we report that at pressures of around 100 GPa, solid oxygen becomes superconducting, with a transition temperature of 0.6 K. The transition is revealed by both resistivity measurements and a Meissner demagnetization signal.