1H, 19F and 77Se NMR measurements were performed to investigate the properties of Bechgaard salts, (TMTSF) 2X, with noncentrosymmetric anions, X=NO3 and FSO 3. Single crystal 77Se NMR signal for NO3 salt detects the spin density wave transition. Preliminary analyses of the angular dependence of 1H NMR spectra were also carried out. Spin density wave in the NO3 salt was confirmed to have an incommensurate wave number and relatively small amplitude. 19F and 77Se NMR signals in the FSO3 salt could detect drastic anomaly at the anion ordering temperature. The insulating state was confirmed to be nonmagnetic with a large spin gap of 420 K.
- Metal-insulator transitions
- Nuclear magnetic resonance spectroscopy
- Organic conductors based on radical cation and/or anion salts