Characteristic SDW and FISDW behavior in (DMET-TSeF)2X system

The quasi one-dimensional system (DMET-TSeF)2X which is similar to (TMTSF)2X is studied. The remarkable magnetic and transport properties for the salts with X=AuI2, AuBr2 and AuCl2 are shown. It is shown from the magnetic measurement that the AuBr2 salt becomes SDW at ambient pressure and its easy-axis is along the most conducting a-axis. FISDW states has been observed for X=AuCl2, AuI2 at ambient pressure and X=AuBr2 under pressure respectively. Low temperature structural analyses have confirmed no superstructure to exist for the AuI2 and AuCl2 salts. Hall effect measurements have revealed the sign change of the Hall voltage(AuI2) and the plateau-like Hall voltage(AuCl2), but at the higher fields than those reported for TMTSF system.