Proton NMR relaxation in the high-Tc organic superconductor β-(BEDT-TTF)2I3

Abstract

We report the measurement of a striking enhancement of the proton spin-lattice relaxation rate occurring at the critical temperature in the high-Tc superconducting state of β(BEDT-TTF)2I3. The T1-1 behaviour is attributed to a logarithmic critical singularity whose amplitude is enhanced by the low-dimensional character of these conductors.