Nmr Evidence For Antiferromagnetic Transition In The Single-Component Molecular System [Cu(Tmdt)(2)]

The magnetic state of the single-component molecular compound [Cu(tmdt)(2)], where tmdt indicates tetramethylene tetrathiafulvalene dithiolate, is investigated by means of H-1 NMR. An abrupt spectral broadening below 13 K and a sharp peak in the nuclear spin-lattice relaxation rate T-1(-1) at 13 K are observed as clear manifestations of a second-order antiferromagnetic transition, which is consistent with the previously reported magnetic susceptibility and electron paramagnetic resonance measurements. The ordered moment is estimated at 0.22 mu(B)-0.45 mu(B) per molecule. The temperature dependence of T-1(-1) above the transition temperature indicates one-dimensional spin dynamics and supports the theory that the spins are on the central part of this molecule, unlike other isostructural compounds.