Ferromagnetic properties and structures of the Mn-implanted GaAs semiconductor

Submicron ferromagnets have been successfully incorporated into semi-insulating (001) GaAs crystals by Mn+ ion implantation and subsequent rapid annealing. Magnetization measurements reveal room-temperature ferromagnetism. The structural and compositional properties of crystallites have been analyzed by transmission electron microscopy, energy dispersion x-ray spectrum, and electron microdiffraction. The results show that crystallites of MnGa and MnAs with a small amount of Ga are formed. Atomic force microscopy and magnetic force microscopy images indicate that the single-domain magnetic state is dominant in submicron ferromagnets under our annealing conditions (750 degrees C-900 degrees C). (C) 2000 American Institute of Physics. [S0021-8979(00)38208-1].Physics, AppliedSCI(E)CPCI-S(ISTP)2