Magnetic phase diagrams of αα-MnMoO4

Field-induced spin-flop transitions in αα-MnMoO4 are summarized in magnetic H–TH–T phase diagrams for different directions of the applied magnetic field up to 12 T. The antiferromagnetic arrangement in the spin-flop phase is preserved at least up to this field for a field parallel to the easy direction. This high transition field is in contrast to the low one of αα-NiMoO4 and favours a model, based on dominant antiferromagnetic supersuperexchange couplings in αα-MnMoO4 over a ferromagnetic Mn4 “cluster” model. The Néel temperature of 9.8(1) K was determined from the corresponding specific-heat anomaly, measured on a single crystal of αα-MnMoO4.