Spin relaxation and magnetic susceptibility studies of HMTSF-TCNQ☆

Abstract The temperature and frequency dependence of the proton spin-lattice relaxation time T 1 , and the temperature dependence of the magnetic susceptibility of HMTSF-TCNQ are reported. The relaxation rate T 1 −1 is slow and only slightly enhanced over the Korringa value. It is frequency-independent (in contrast with TTF-TCNQ), indicating a stronger interchain coupling. The susceptibility is weakly paramagnetic above 100 K, suggesting (together with the T 1 data) an effective mass m ∗ ≅ 2m e in this temperature range. Below 100 K, χ becomes diamagnetic, saturating at 30 K. This diamagnetism is characterised as Landau-Peierls (orbital) diamagnetism, due to a more 3-dimensional character of the electronic states of HMTSF-TCNQ as the temperature is lowered from 100 K to 30 K.