ABSTRACTThe purpose of this talk is to discuss the physical properties of the (TMTSF)2X charge transfer salts in high magnetic fields. This class of materials is of great interest since the effective lower dimensionality and the various ground states are magnetic field dependent at low temperatures. At present, the so-called “standard model” provides a good theoretical description of the low field field induced spin density wave transitions (FISDW). However the reentrance from the last FISDW back to a high field metallic state, and the coexistence of “fast oscillations” in all measured properties, is yet to be accurately described theoretically. The emphasis of this paper is on recent specific heat results which have been obtained on (TMTSF)2ClO4 in magnetic fields as high as 30 T. Here we observe both the reentrant phase transition and the fast oscillations in the specific heat. A main conclusion we draw from our measurements is that the density of states in the reentrant phase is less than it is in the low field metallic state at low temperatures.
