One of the most direct evidence for absence of magnetic ordering give NMR or μSR experiments. If there is a local magnetic field present, the nuclear or muon spin would be affected which can be measured. H- NMR measurements on κ-(BEDT-TTF) 2 Cu 2 (CN) 3 have shown no sign of magnetic ordering down to 32 mK, which is four orders of magnitude smaller than the coupling constant J≈250 K between neighboring spins in this compound. Further investigations include: