A new method to enhance the magnetism of Fe overlayer on GaAs(100): Sulfurpassivation using CH3CSNH2

Ferromagnetic resonance (FMR) has been used to investigate the magnetism of Fe overlayer on S-passivated GaAs(100) pretreated by CH3CSNH2. Comparing w ith the magnetism of Fe overlayer on clean GaAs(100), we find that sulfur p assivation can prevent As diffusion into Fe overlayer and weaken the intera ction of As and Fe. It results in enhancing the magnetism of Fe overlayer o n GaAs(100). We also investigate the effects of the pre-annealing of S- pas sivated GaAs(100) substrate on the magnetism of Fe overlayers. The results show that the maximum effective magnetization can be obtained at annealing temperature of 400 degrees C. According to the experimental results of sync hrotron radiation photoemission, it can be explained by the change of chemi cal composition and surface structure of the passivation layer on GaAs(100) surface after the annealing.