μ+SR as a probe of anisotropy in low-dimensional molecular magnets

Abstract We describe how muon–spin rotation ( μ + SR ) can be particularly effective in determining the onset temperature of 3D ordering in low-dimensional molecular magnets, even when the low dimensionality means that this transition is masked in data from bulk thermodynamic probes such as heat capacity measurements. We illustrate the use of μ + SR with various copper-based magnets, including copper pyrazine dinitrate, Cu ( C 4 H 4 N 2 ) ( NO 3 ) 2 , which orders below 0.107 K, and also for the organic radical-ion salt DEOCC- TCNQF 4 which appears to be one of the most ideal examples of 1D S = 1 2 Heisenberg antiferromagnets yet discovered.