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

Abstract

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, σ_RT∼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.