MnAs nanoclusters embedded in GaAs studied by x-ray diffuse and coherent scattering -: art. no. 235206

The structure of phase-separated (Ga, Mn)As, annealed at high temperature (similar to700 degreesC), is studied by x-ray diffraction techniques. Analysis of the x-ray diffuse and coherent scattering reveals two types of clusters: (1) small clusters detected by diffuse scattering through the distortions they produce in the host matrix and (2) larger clusters with MnAs structure giving rise to coherent diffraction peaks. The average sizes for the two cluster types are estimated to be 5 and 18 nm, respectively. The smaller clusters are found to be of vacancy type. Their density is estimated to be 1.8x10(16) cm(-3). The hexagonal lattice of the larger MnAs crystallites is found to be compressed along the [(2) over bar 110] direction by -0.49% with respect to the bulk hexagonal MnAs lattice. The host zinc blende matrix is found to be under a -0.20% tensile strain.