Figure 3

(a) Normalized magnetization of Tb and Co as a function of the laser fluence. \(M_z/M_s\) ratios were extracted from the magnetization curves of two different simulations of the [\(\text {Tb}_1\)/\(\text {Co}_2\)] system. (b) Time evolution of the magnetization of Tb and Co sublattices, \(\text {M}^\text {Co}\) (blue) and \(\text {M}^\text {Tb}\) (red), after the application of a single laser pulse at t = 7 ps in the system [\(\text {Tb}_1\)/\(\text {Co}_2\)] for two different fluences: 40 mJ/\(\text {cm}^2\) (top) and 42 mJ/\(\text {cm}^2\) (bottom). The two different events for each fluence value are represented by the solid and dashed lines. Inset: \(M_Z\)/\(M_S\) during 7.6 \(<t<\) 8.4 ps. Evolution of the electronic temperature after the single laser pulse interacts with the system at t = 7 ps (pink background). The single laser pulse duration is 50 fs. (c) Magnetization of Tb and Co sublattices in a magnetization phase map. Upper inset: Pathways followed by the magnetizations in a vicinity of zero. The magnetic moment of the Co sublattice always crosses zero before the magnetic moment of the Tb sublattice. Lower inset: Magnetization of the sublattices as a function of the temperature. The effective Curie temperature of the system is close to 750 K.