¹H NMR in Organic Superconductor β-(BEDT-TTF)₂I₃

Abstract

Pulsed 1 H NMR is applied to β-(BEDT-TTF) 2 I 3 between 1.7 K and room temperature. The spin-lattice relaxation time T 1 shows a typical metallic character ( T 1 T =constant) below ∼100 K. This is consistent with a picture of two dimensional metal. Above ∼100 K T 1 -1 is governed by thermal motion of ethylene groups in BEDT-TTF molecule. The line width studies shows that this thermal motion starts to freeze at ∼195 K, very near the onset temperature of incommensurate superstructure.