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

We describe how muon–spin rotation (μ+SR)(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+SRμ+SR with various copper-based magnets, including copper pyrazine dinitrate, Cu(C4H4N2)(NO3)2Cu(C4H4N2)(NO3)2, which orders below 0.107 K, and also for the organic radical-ion salt DEOCC-TCNQF4TCNQF4 which appears to be one of the most ideal examples of 1D S=12 Heisenberg antiferromagnets yet discovered.