DIPOLAR INTERACTIONS IN THE DILUTE ANTIFERROMAGNET IN A UNIFORM-FIELD

We examine the role played by dipolar interactions in the equilibrium critical behaviour of the dilute antiferromagnet in a uniform field (DAFF). The DAFF has been known to map onto a random field model, and we perform a similar mapping, only this time including dipolar interactions. We conclude that dipolar forces affect the DAFF in a way no different from the case for the corresponding pure system. Dilution does not generate any additional long-range forces or other effects arising from dipolar forces. In particular, in the final random field model which the DAFF maps onto, we find that the mean-field propagator is unaffected by the inclusion of dipolar interactions save for some constant terms. We restrict our work to the critical region close to the transition temperature and assume a domain-free state.