Domain growth by isothermal aging in 3d Ising and Heisenberg spin glasses

Non-equilibrium dynamics of three dimensional model spin glasses - the Ising system Fe${}_{0.50}$Mn${}_{0.50}$TiO${}_3$ and the Heisenberg like system Ag(11 at% Mn) - has been investigated by measurements of the isothermal time decay of the low frequency ac-susceptibility after a quench from the paramagnetic to the spin glass phase. It is found that the relaxation data measured at different temperatures can be scaled according to predictions from the droplet scaling model, provided that critical fluctuations are accounted for in the analyzes.