Temperature dependence of the magnetization of Fe films on Cu(1 0 0) studied by SPMDS and SMOKE: effects of relaxation

Temperature dependence of the magnetization of Fe films on Cu(1 0 0) has been investigated by spin-polarized metastable deexcitation spectroscopy (SPMDS), which is extremely surface sensitive, and by surface magneto-optic Kerr effect (SMOKE). It has been observed that the remanent magnetization measured by the two methods exhibits different behaviors at around the critical temperature. This has been found to be caused by the relaxation of the magnetization. The relaxation may be caused by the formation of the multi-domain state or the effect of superparamagnetism.