Finite size effects on spin glass dynamics

The recent identification of a time and temperature dependent spin glass co rrelation length, xi(t(omega),T), has consequences for samples of finite si ze. Qualitative arguments are given on this basis for departures from t/t(w ) scaling for the time decay of the thermoremanent magnetization, M-TRM (t, t(omega), T), where t is the measurement time after a "waiting time" t(ome ga) and for the imaginary part of the ac susceptibility, chi "(omega, t). C onsistency is obtained for a more rapid decay of M-TRM(t, t(omega), T) With increasing t(omega) when plotted as a function of t/t(omega) for the devia tion of the characteristic time for M-TRM(t, t(omega), T) from a linear dep endence upon H-2 at larger values of H, and for the deviation of the decay of chi "(omega, t) from omega t scaling upon a change in magnetic field at large values of omega t. These departures from scaling can, in principle, b e used to extract the particle size distribution for a given spin glass sam ple.