Electrical properties of MEM(TCNQ)2

Detailed studies of the dc and microwave conductivity and dielectric constant of the quasi-one-dimensional conductor, MEM(TCNQ) 2 for 4.2 K < T < 360 K are presented. Particular attention is paid to the strong first-order transition at 335 K where the conductivity jumps by about three orders of magnitude on heating and the activation energy for the conductivity disappears. These electrical data are compared to previously published magnetic susceptibility measurements and to recent structural, heat capacity, and nmr data. The role of Coulomb interactions, in determining the temperature dependence of the conductivity, the susceptibility, and the structure, is emphasized.