Investigation of critical properties in the two-dimensional site-diluted Ising ferromagnet

The quenched site-diluted Ising ferromagnet, with a probability p for site occupation, is studied on a square lattice. A method, based on self-organized criticality, drives the system spontaneously to the critical point, providing an efficient way to estimate critical properties for different values of p. In spite of the small lattice sizes used, the method yields critical temperatures and exponents in fairly good agreement with recent extensive numerical analyses. In particular, the slope of the ferromagnetic–paramagnetic boundary near p=1 is very close to the well-known exact value. Our critical-exponent estimates follow, within the error bars, in the same universality class of the pure Ising ferromagnet.