Self-averaging of random and thermally disordered diluted Ising systems

Self-averaging of singular thermodynamic quantities at criticality for randomly and thermally diluted three-dimensional Ising systems has been studied by the Monte Carlo approach. Substantially improved self-averaging is obtained for critically clustered (critically thermally diluted) vacancy distributions in comparison with the observed self-averaging for purely random diluted distributions. Critically thermal dilution, leading to maximum relative self-averaging, corresponds to the case when the characteristic vacancy ordering temperature (theta) is made equal to the magnetic critical temperature for the pure three-dimensional (3D) Ising systems (T(3D)(c)). For the case of a high ordering temperature (theta>>T(3D)(c)), the self-averaging obtained is comparable to that in a randomly diluted system.