MONTE-CARLO SIMULATIONS OF A SIMPLE ISING SPIN MODEL REPRESENTING 111 AND 100 NICKEL IRON MULTILAYERS

The magnetic behaviour of FCC superlattices of equal-thickness Ni and Fe layers, with repeat lengths between 6 and 30 atomic layers, and with layers parallel to both 111 and 100 crystal planes, is modelled with a short range interaction Ising model, using parameters determined from a previous study of homogeneous Ni(c)Fe1-c alloys. The ground states of these models and the dependence of their magnetizations on temperature and magnetic field are studied using Monte Carlo simulation. We pay particular attention to macroscopic manifestations of the antiferromagnetic coupling between the Fe sites, and the surprisingly strong ferromagnetic Ni-Fe coupling deduced from the simulations of the solid solutions. We suggest experiments which would critically test the model.