Abstract
The effects of a magnetic field on spin glass dynamics are explored for a Cu0.887Mn0.113 thin film of thickness L = 20 nm in a multilayer configuration. An experimental protocol removes uncertainties associated with the time dependence of the field-cooled magnetization MFC(t,T). Activated dynamics is exhibited after the spin glass correlation length ξ(t,T) has reached L, creating a quasiequilibrium state. Here, the activation energy depends upon the strength of the magnetic field H. The magnitude of the activation energy diminishes as H2, the coefficient of which is proportional to the number of correlated spins. A quantitative fit requires a “pancakelike” correlated region, associated with the T = 0 phase transition for a spin glass in D = 2 dimensions.