Probing spin-glass dynamics with 1/f Noise

We have measured the 1/f noise in the electrical resistance of CuMn wires of varying thickness (10nm-80nm) in order to explore the dynamics of the spin-glass state. We use a cooling protocol suitable for comparison between experiment and recent simulations. We use the fluctuation dissipation theorem to compare our measurements with earlier measurements made of the out-of-phase component of the ac susceptibility in thin films and find good agreement. The frequency dependence of the noise indicates a crossover from two-dimensional to three-dimensional dynamics with increasing thickness. We provide a physical interpretation of a previously phenomenological result for this frequency dependence.