Electric and Magnetic Properties of an Organic Ion-Radical Salt: 1,1′-Diethyl-2,2′-Cyanine-[TCNQ]₂

Abstract

The temperature dependence of the electric conductivity, the magnetic susceptibility and the ESR spectra of the crystals of an organic ion-radical salt, 1,1′-diethyl-2,2′-cyanine-[7,7′,8,8′-tetracyanoquinodimethane]₂, were measured. The electric conductivity, σ, is fairly large at room temperature (σ_RT=3.5 Ω⁻¹cm⁻¹) and shows a semiconductive temperature dependence, of which activation energy decreases with decreasing temperature. The susceptibility obeys Curie-Weiss’ law above 60 K and shows a maximum near 40 K. Below 15 K the susceptibility increases again with decreasing temperature. However, similarly at high temperatures even at 4.2 K there are two intense ESR absorptions of which interval depends on the orientation of the crystal in the applied magnetic field.