Picosecond magnetization dynamics of the Gd(0 0 0 1) surface

Abstract The magneto-induced fraction of the optical second harmonic reflected from Gd(0 0 0 1) surfaces was studied in pump–probe experiments as a function of temperature. The magnetic contrast in thermal equilibrium and at 1 ps pump–probe delay show a similar temperature dependence, but at 1 ps delay the magnetic contrast is reduced to 30% due to ultrafast demagnetization. Compared to lattice cooling the magnetization recovery is significantly slower within the first 150 ps and, therefore, does not obey the typical M ( T ) behavior in this time range. This is attributed to the localized character of the 4f electrons carrying the large magnetic moment in Gd.