Field effect on the dynamics of the Ising spin glass near the percolation threshold

The effect of a uniform field H on the dynamics of the Ising spin glass FexZn1-xF2, x=0.25, is studied through Monte Carlo simulations. The correlation function data are consistent with the droplets picture, with a single scaling variable t/tw, where tw is the waiting time under H, activation over logarithmic energy barriers near the percolation threshold, xp=0.24, and considerable change of the glassy phase for intermediate and high H.