Effects of disorder and magnetic field in frustrated magnets

In this work a site diluted antiferromagntic Ising model in the FCC lattice is studied by Monte Carlo simulation. At low temperatures, we find that as the external field is increased the transition from the antiferromagnetic phase to the superantiferromagnetic one occurs through an intermediate phase which is not present in the undiluted system. This new phase ordering has three distinct values for the sublattice magnetizations corresponding to one of the phases found in a recent mean field calculation thus suggesting that in strongly frustrated systems many novel spins ordering may arises as found experimentally, for instance, in some pyrochlores.