SDW phase of (TMTSF)2PF6 at high magnetic fields

The magnetic field dependence of the spin-density-wave (SDW) transition temperature T SDW in (TMTSF) 2 PF 6 for various pressure has been measured with the field parallel to the c * axis. A quadratic behavior of the magnetic field dependence of T SDW is observed for all pressure. With increasing pressure, T SDW decreases and the coefficient of the quadratic term increases. From these behaviours, T SDW for the perfect nesting case is estimated as about 16K using a mean field theory. This means that even at the ambient pressure where T SDW is 12K, the SDW phase of (TMTSF) 2 PF 6 is fairly suppressed by the two-dimensionality of the system.