The role of S passivation on magnetic properties of Fe overlayers grown onGaAs(100)

We have produced epitaxial Fe overlayers on sulfur-passivated GaAs(100) sur faces by CH3CSNH2 treatment, and investigated the correlation between magne tic properties of the overlayers and surface chemical structure of GaAs(100 ) surfaces by ferromagnetic resonance and synchrotron radiation photoemissi on. The surface chemical properties were modified by changing the annealing temperature of the surfaces prior to the growth. The results show that the magnetization of Fe overlayers is crucially determined by the presence of Ga-S chemical bonds and excess As after the anneals. A comparative investig ation of the magnetization has been made on both S passivated and clean GaA s(100). It is confirmed that S passivation on the GaAs surface can effectiv ely eliminate the magnetization deficiency previously attributed to interdi ffusion of As into the Fe overlayer. (C) 1999 American Institute of Physics . [S0021-8979(99)06913-3].