Renormalization group phase boundary of the three-dimensional bond-dilute Ising ferromagnet

Abstract

The phase boundary (as well as the thermal-type critical exponents) associated to the quenched bond-dilute spin-1/2 Ising ferromagnet in the simple cubic lattice is approximately calculated within a real space renormalization group framework in two different versions. Both lead to qualitatively satisfactory critical frontiers, although one of them provides an unphysical fixed point (which seems to be related to the three-dimensionality of the system) besides the expected pure ones; its effects tend to disappear for increasingly large clusters. Through an extrapolation procedure the (unknown) critical phase boundary is approximately located.