Nonlinear dynamic susceptibilities at the spin-glass transition of Ag:Mn

We have measured the ac nonlinear susceptibilities ₃^', ₅^', and ₇^' of very dilute Ag: Mn spin-glasses above and below the transition temperature T₆ as functions of frequency, temperature, and magnetic field. In the static limit, these quantities display well defined critical singularities at T₆. The nonlinear susceptibilities can be fitted above T₆ by powers of frequency with weakly temperature-dependent exponents. While the effective exponents satisfy the relations imposed by static and dynamic scaling, the observed temperature and frequency roundings suggest the presence of additional length scales.