Organic magnetic materials studied by positive muons

Positive muons can be implanted into organic and molecular magnets in order to study their internal magnetic field distribution and any associated dynamics. The muon behaves essentially as a "microscopic magnetometer", sensitive to local magnetic order and magnetic fluctuations. We describe some recent experiments using this technique which were performed on a variety of organic systems, including nitronyl nitroxide magnets and materials with spin-Peierls ground states, MF-M(TCNQ)(2) and DEM(TCNQ)(2), and demonstrate how the technique can give information concerning their ground states.