The electrical and magnetic properties of (TTF)(I)0.71

The synthesis and transport properties of the salts (TTF) (iodine)x have been investigated. These salts are quasi-one-dimensional compounds containing cation radicals only, in contrast to the cation radical–anion radical systems such as (TTF)(TCNQ). The phase diagram of (TTF)(I)x is discussed, and found to consist of two conducting, stoichiometric phases, x=2.0 and 3.0, and two nonconducting, nonstoichiometric phases, x=0.71 and 2.3. The transport properties of (TTF)(I)0.71 are discussed in detail. This phase is highly conducting, σRT∼350 Ω−1⋅cm−1, undergoes a sharp transition to a less conducting state at ∼210 °K, and exhibits an unusual hysteresis in some of the transport properties upon thermal cycling. The nature of the high temperature ground state is examined.