Abstract
Experiments involving measurements of the dependence on time of the thermoremanence magnetization of two-dimensional random magnets are described. The low temperature values for the magnetic viscosity agree well with both current theories of tunneling of the magnetization vector (Chudnovsky et al. ) and the work of Grabert et al . who predicted that the transition from classical to quantum regime is rather sharp for undamped systems. An Ag/Tb /Ag multilayer is discussed.