Magnetic susceptibility of (DMe–DCNQI)2Li1−xCux

We measured the static spin susceptibility of the quasi-one-dimensional molecular conductors, (DMe–DCNQI)2Li1−xCux (0≤x≤1). We separated the susceptibility component due to itinerant electrons from that due to local magnetic moments by assuming that the temperature dependence of the latter component obeys the Curie–Weiss law. From the temperature dependence of the former component, we conclude that the ground state of this system is nonmagnetic for x≤0.14 and paramagnetic for 0.17≤x. The phase boundary thus determined is consistent with the phase diagram already determined by resistivity measurements.