Abstract
Solid oxygen is the only elementary molecular magnet. Under the very high pressure of 96 GPa oxygen transforms into a metal and a superconductor. Theory predicts a nonmagnetic state occurring before the transition into the superconducting phase. Nevertheless, until now there was no direct evidence of a magnetic collapse in high-pressure oxygen. For the first time direct information is provided on magnetic properties of the phase, which is sandwiched between the antiferromagnetic phase and the superconducting phase. We used magnetic neutron diffraction. The data show that the long-range magnetic order disappears at the transition. The magnetic collapse occurs at , far below the pressure of the insulator-metal (superconductor) transition. The collapse is preceded by a decrease in temperature of transition towards the long-range magnetically ordered state () in the phase, at .
- Received 21 January 2005
DOI:https://doi.org/10.1103/PhysRevLett.94.205701
©2005 American Physical Society