Collapse of the effective response time near the spin glass transition temperature

Kenning et al. discovered the collapse of the effective response time, t_H^eff(t_w;T), independent of aging time, t_w, as one approached the spin glass transition temperature T_g from below.  Nordblad and Lundgren observed the same effect by reducing the temperature from T_g(H).  We analyze the behavior of ln t_H^eff(t_w;T) in the temperature range near and below T_g using a scaling law that takes into account both the magnetic field H and the time-dependent spin-glass coherence length ξ(t,t_w;T). An over-determined predictive fit to the experimental data accounts for a quasi-oscillatory structure of ln t_H^eff(t_w;T) as a function of magnetic field H² for reduced temperatures as large as T/T_g = 0.98.