Effect of doping (TMTSF)2ClO4 with TMTTF - I. Ambient pressure results : a competition between the different possible ground states

Abstract

We report on transport and EPR studies of (TMTSF)2ClO4 doped with TMTTF. The role of doping by the sulphur analog on the high temperature metallic range is presented and discussed; nevertheless a large part of this work is devoted to the low temperature behaviour. The 3d superconductive phase which occurs around 1 K under ambient pressure in the pure TMTSF salt is shown to be quickly suppressed. The doping process favours the stabilization of an insulating phase at low temperature and the change with increasing doping of the magnetic properties is explained as a cross-over from a SDW to a non-magnetic ground state; a phenomenological model is discussed to support these experimental results