ANTIFERROMAGNETIC-RESONANCE IN THE LINEAR-CHAIN CONDUCTING POLYMERS RBC60 AND CSC60

Antiferromagnetic resonance has been observed in powders of the conduc ting alkali fulleride linear polymers, RbC60 and CsC60, at high freque ncies (75, 150, and 225 GHz). This is proof for an antiferromagnetical ly ordered ground state and shows that these systems are not spin glas ses. The sublattice magnetization is independent of applied magnetic f ield up to at least 8 T. Magnetic fluctuations are observed between 35 and 50 K. Comparison with the spin-density-wave system (TMTSeF)(2)PF6 clearly shows that these polymers are also quasi-1D spin-density-wave systems with 3D ordering at low temperatures, as suggested previously .