OVERALL TIME EVOLUTION IN PHASE-ORDERING KINETICS

The phenomenology from the time of the quench to the asymptotic behavi or in the phase-ordering kinetics of a system with a conserved order p arameter is investigated in the Bray-Humayun model [Phys. Rev. Lett. 6 8, 1559 (1992)] and in the Cahn-Hilliard-Cook model [J. Chem. Phys. 28 , 158 (1958); Acta Metall. 18, 297 (1970)]. From the comparison of the structure factor in the two models the generic pattern of the overall time evolution, based on the sequence ''early linear-intermediate mea n field-late asymptotic regime'' is extracted. It is found that the ti me duration of each of these regimes is strongly dependent on the wave vector and on the parameters of the quench, such as the amplitude of the initial fluctuations and the final equilibrium temperature. The ri ch and complex crossover phenomenology arising as these parameters are varied can be accounted for in a simple way through the structure of the solution of the Bray-Humayun model. [S1063-651X(98)10310-0].