Submicron GaMn quasicrystals in ferromagnetic GaAs

GaMn icosahedral particles with quasicrystalline order have been found in Mn implanted and rapidly annealed GaAs by means of selected-area electron diffraction, high-resolution, and dark-field electron microscopy. The orientation relationship between the submicron quasicrystals with the icosahedral (2/m 3̄5̄) symmetry and the face-centered cubic (fcc) GaAs matrix is determined to be: i5̄ (the fivefold inversion axis in (2/m 3̄5̄))//[110]GaAs, i3̄ (the threefold inversion axis)//[111̄]GaAs, and i2 (the twofold axis)//[121̄]GaAs. The statistics of these structural studies, combined with magnetic force microscopy, indicate that the submicron quasicrystals are ferromagnetic.