Pre-asymptotic critical behavior and effective exponents in disordered   metallic quantum ferromagnets
  We determine the pre-asymptotic critical behavior at the quantum ferromagnetic transition in strongly disordered metals. We find that it is given by effective power laws, in contrast to the previously analyzed asymptotic critical behavior, which is valid only in an unobservably small region. The consequences for analyzing experiments are discussed, in particular ways to distinguish between critical behavior and Griffiths-phase effects. 
T.R. Kirkpatrick and D. Belitz
cond-mat.str-el