Scaling of the magnetic linear response in phase-ordering kinetics

The scaling of the thermoremanent magnetization and of the dissipative part of the non-equilibrium magnetic susceptibility is analysed as a function of the waiting time s for a simple ferromagnet undergoing phase-ordering kinetics after a quench into the ferromagnetically ordered phase. Their scaling forms describe the crossover between two power law regimes governed by the non-equilibrium exponents a and lambda(R)/z, respectively. A relation between a, the dynamical exponent z and the equilibrium exponent eta is derived from scaling arguments. Explicit tests in the Glauber-Ising model and the kinetic spherical model are presented