TRANSPORT EVIDENCE FOR NEW PHASE-CHANGES IN 1T-TAS(2) AFTER INTERCALATION WITH HYDRAZINE

In this paper, we present evidence, from simultaneous electrical resis tivity and thermogravimetric measurements, for a phase transition occu rring at approximately 378 K in the charge-density-wave system IT-TaS2 when fully intercalated with hydrazine and then heated in a hydrazine environment. We discuss this change in terms of a transition between a commensurate (square-root 7/8)alpha x (square-root 7/8)alpha* x (sq uare-root 7/8)alpha superlattice already known to exist at room tempe rature in the intercalated material, and a weaker incommensurate disto rtion. We also discuss the effect of hydrazine intercalation on the 28 2 K transition observed on warming in pure IT-TaS2, and give further e vidence for the partial inter-layer character of this transition.