Journal of Statistical Physics, Vol. 54, Nos. 3/4, 1989. p. 755-763.
We study the thermodynamic behavior of a two-component random ferromagnetic Ising system in the presence of given boundary conditions. The system consists of two species A and B occupying the sites of a Bethe lattice
which terminates on a surface layer where the spins are kept fixed. We study the interface of the system when the spins on half of the surface of the lattice are fixed opposite to the spins on the other half. More specifically, we study the influence of disorder on the interface width. We find that disorder clearly increases the interface width at temperatures well below To, indicating that the interface roughening of disordered Ising systems in 3D real lattices should occur at temperatures significantly below those of the corresponding ordered ones.