Proton spin-lattice relaxation at low temperatures in quinolinium (TCNQ) 2

Abstract

Measurements of the proton spin-lattice relaxation rate ( T 1) -1 in the quasi-one-dimensional organic charge transfer salt quinolinium (TCNQ) 2 are reported over the magnetic field ( H) range 1.2–10 kOe and the temperature ( T) range 0.03–55 K. In the low temperature range (defined by gμ B H ⪆ kT) the relaxation shows an activation energy type of behavior; T -1 1 = B exp [- ϵ( H)/ kT], B = (15.0 ± 2.5) sec -1, and the activation energy (ϵ) is given by ϵ = AH δ , with δ = 1.65 ± 0.10 and A = (1.76 ± 0.34) x 10 -2 K ( kOe) -1.65. The mechanism responsible for this behavior is not yet identified.