The experimental status on the question of a phase transition in spin glasses

Abstract

Following a brief introduction to spin-glass systems, the current status of experimental evidence on the occurrence of a phase transition is reviewed. Recent analyses of dynamical properties of spin glasses are discussed in terms of several model predictions, including the conclusion of a divergent relaxation time τ at a finite temperature, although with large, non-mean-field indices z and v. The role of regular terms (leading to corrections to scaling) in the nonlinear response are reviewed, stressing their influence on the evaluation of the susceptibility and order-parameter exponents γ′ and β′.