The FI-SDW formation in (TMTSF)2ClO4 investigated in the infrared

From a magneto-optical study on (TMTSF) 2 ClO 4 we determine the SDW gap as a function of magnetic field and temperature. The transition temperatures found for the resolved FI-SDW subphases mimic the established phase diagram. Furthermore, the data confirm the existence of a collective excitation of the SDW condensate at relatively high frequency, which implies that this mode is pinned rather strongly to the lattice. In additon, we observed an interesting relaxation effect near the N=0 phase transition