Role of initial conditions in spin-glass aging experiments

The effect of initial conditions on aging properties of the spin-glass state is studied for a single crystal Cu:Mn 1.5 at %. It is shown that the memory of the initial state, created by the cooling process, remains strong on all experimental time scales. The t/tw scaling properties of two relaxation functions, the thermoremanent magnetization (TRM) and the isothermal remanent magnetization (IRM) (with tw1=0 and tw2=tw), are compared in detail. It is observed that the IRM relaxation as a function of t/tw demonstrates a superaging behavior. This result suggests that the subaging, exhibited by the TRM decay, arises from the influence of the cooling process, and cannot be considered a natural type of scaling in spin-glass dynamics.