Order-Disorder Transitions under Confinement

The phase transitions in Ising thin films with antiferromagnetic interactions are studied as a function of the surface field h for symmetry-preserving surface orientations. It is found that for very large h an N-layer system undergoes a separation between its surfaces and the (N-2) inner layers. The system comprised of the surfaces and the inner layers displays a rather unusual phase diagram with a disordered phase lying between the ordered …