DAMAGE-SPREADING SCALING AND TEMPORAL EVOLUTION NEAR THE SURFACE-BULKTRANSITION OF ISING LAYERED FILMS

The spreading of damage in layered S = 1/2 Ising ferromagnetic thin fi lms with an enhanced surface coupling constant is investigated through the Metropolis dynamics. Motivated by the technological interest in d eveloping high-quality magnetic films, we study how a damage introduce d in the magnetic configuration of a previously chosen layer becomes d istributed along the whole film. For a 12-layer thick film, we obtain that, near the bulk critical spreading temperature, the Hamming distan ce profile changes its shape from a positive curvature profile for J(s )/J < 1.4 to a negative curvature profile for J(s)/J > 1.4, exhibiting quite flat profiles for J(s)/J similar or equal to 1.4, which is a si gnature of the reminiscent special surface-bulk transition which occur s in the semi-infinite system. Furthermore, the temporal evolution of the damage front is followed and it shows quite distinct regimes near and above the bulk critical spreading temperature, changing from a typ ical exponential growth above criticality to a diffusive-like behavior in the critical region.