A high-resolution electron microscopy study of β-SiC nanoparticles formed by C+-implantation of single crystal silicon with subsequent annealing has been carried out. The as-implanted sample had a trilayered structure, in which the surface layer, A, and the bottom layer, C, were crystalline but damaged, and the middle layer, B, was amorphous. After annealing this structure, β-SiC particles were formed throughout the trilayered structure but with different forms: a few epitaxial β-SiC nanoparticles in layers A and C, and more random nanoparticles in layer B. The β-SiC nanoparticles, in the size range 2-8nm, should be responsible for the blue-emitting effect of the silicon-based porous β-SiC

The structures and magnetic properties of R,(Fe1-xSix)17 compounds (R=Dy,Y) were investigated by x-ray phase analysis and magnetic measurements. It is shown that Si substitution for Fe leads to a phase transition at x=0.2, and that the mean iron magnetic moment, ufe of R2(Fe1-xSx)17 compounds (R=Dy,Y) decreases as Si concentration x increases; moreover, there is a maximum of dependence Tc(x) at about x=0.16. It is found that the exchange interaction constant AFeFe inR2(Fe1-xSix) compounds (R=Dy, Y) increases with x increasing by means of means-molecular-field analysis of Tc 0 1994 American Institute of Physics.