Spin diffusion and magnetic eigenoscillations confined to single molecular layers in the organic conductors kappa-(BEDT-TTF)2Cu[N(CN)2]X (X=Cl,Br).

The layered organic compounds, kappa-(BEDT-TTF)2Cu[N(CN)2]X X=Cl, Br) are metals at ambient temperatures. At low temperatures, the Cl compound is a weakly ferromagnetic Mott insulator while the isostructural Br compound is a superconductor. We find by conduction electron spin resonance and antiferromagnetic resonance (AFMR) an extreme anisotropy of spin transport and magnetic interactions in these materials.