Antiferromagnetic resonance in tetramethyltetrathiafulvalene (TMTTF) salts

Abstract

Antiferromagnetic resonance has been observed in two Bechgaard tetramethyltetrathiafulvalene salts, (TMTTF${)}_2$SCN and (TMTTF${)}_2$ ${\mathrm{SbF}}_6$ below 9 and 6 K, respectively. The results are quantitatively described using antiferromagnetic resonance theory and compared with those previously obtained for other salts of the series. A rotation of the magnetic axes with respect to the crystallographic frame is unambiguously found and attributed to the triclinic symmetry of these salts. The relevant parameters of the antiferromagnetic ground state, including the Néel temperature and the spin-flop field, are also deduced. Finally a comparison with the magnetic properties of the other Bechgaard salts is made.