METAMAGNETS IN UNIFORM AND RANDOM-FIELDS

We study a two-sublattice Ising metamagnet with nearest-and next-neare st-neighbor interactions, in both uniform and random fields. Using a m ean-field approximation, we show that the qualitative features of the phase diagrams are significantly dependent on the distribution of the random fields. In particular, for a Gaussian distribution of random fi elds, the behavior of the model is qualitatively similar to a dilute I sing metamagnet in a uniform field.