Ferromagnetic properties and structures of the Mn-implanted GaAs semiconductor

Submicron ferromagnets have been successfully incorporated into semi-insula ting (001) GaAs crystals by Mn+ ion implantation and subsequent rapid annea ling. Magnetization measurements reveal room-temperature ferromagnetism. Th e structural and compositional properties of crystallites have been analyze d by transmission electron microscopy, energy dispersion x-ray spectrum, an d electron microdiffraction. The results show that crystallites of MnGa and MnAs with a small amount of Ga are formed. Atomic force microscopy and mag netic force microscopy images indicate that the single-domain magnetic stat e is dominant in submicron ferromagnets under our annealing conditions (750 degrees C-900 degrees C). (C) 2000 American Institute of Physics. [S0021-8 979(00)38208-1].