Effects of random fields in an antiferromagnetic Ising spin glass

The effects of random fields on the two-sublattice infinite-ranged Ising sp in-glass model are investigated. This model is expected to be appropriate a s a mean-field description of antiferromagnetic spin glasses such as FexMn1 -xTiO3. Within replica-symmetric calculations, we study the influence of Ga ussian and bimodal random fields on the phase transitions and phase diagram s. It is shown that, in the presence of random fields. the first-order tran sitions are weakened and may become continuous. Also, the antiferromagnetic phases are always destroyed by sufficiently strong random fields. A qualit ative comparison with existing experimental results and the limitations of the present calculations are discussed.