Incompleteness of the Critical Exponent Description for Ferromagnetic Systems Containing Random Impurities

We consider the magnetic properties and spin correlation functions of a two-dimensional Ising model with random impurities near the critical temperature and find that the usual parametrization provided by the exponents γ, δ, and η and the correlation length ξ for TTc does not describe our results. Experimental implications of this breakdown of the critical exponent forms are discussed.