Pickup, R M.; Cywinski, R.; Pappas, C.; Farago, B.; Fouquet. P.: Generalized Spin-Glass Relaxation. Physical Review Letters 102 (2009), p. 097202/1-4
10.1103/PhysRevLett.102.097202
Abstract:
The time dependent spin autocorrelation function of a number of CuMn and AuFe canonical spin glasses has been determined by neutron spin echo spectroscopy. The spin autocorrelation is found to follow the same generalized exponential relaxation function both above and below the glass temperature. This function explicitly introduces macroscopic interactions and hierarchically constrained dynamics. The associated interaction parameter can be directly related to a normalized Tsallis non-extensive entropy parameter which in turn is found to exhibit a universal scaling with reduced temperature.