Local magnetism in the molecule-based metamagnet [Ru-2(O2CMe)(4)](3)[Cr(CN)(6)] probed with implanted muons

We present a muon-spin relaxation study of local magnetism in the molecule-based metamagnet [Ru2(O2CMe)4] 3[Cr(CN)6]. We observe magnetic order with T N=33 K, although above 25 K the sublattice spins become less rigid and a degree of static magnetic disorder is observed. The comparison of measurements in applied magnetic field with simulations allows us to understand the origin of the muon response across the metamagnetic transition and to map out the phase diagram of the material. Applied hydrostatic pressures of up to 6 kbar lead to an increase in the local magnetic field along with a complex change in the internal magnetic-field distribution. © 2011 American Physical Society