Dilute semi-infinite Ising model

Abstract
The influence of bond and site dilution on the phase transitions of a semi-infinite three-dimensional Ising model is investigated. To determine, in particular, phase diagrams two different techniques have been used: an extension of Migdal's approach to disordered systems and a more tractable approximation introduced recently. Temperature-concentration phase diagrams for fixed values of the ratio of surface and bulk interactions can exhibit five different types of phase transitions.