An EXAFS investigation of the local structure of R8Mg42Zn50 icosahedral quasicrystals (R=Y, Dy)

EXAFS experiments have been performed on the icosahedral quasicrystals R8Mg42Zn50 (R=Y, Dy) at the Y K, Dy LIII and Zn K edges. Isomorphism of Y- and Dy-based quasicrystals is clearly evidenced. The rare earth is found to be essentially surrounded by Zn atoms with a small amount of Mg atoms. The surrounding of Zn appears less spherical than that of the rare earth and includes the three elements in almost stoichiometric proportion. The relation between structure and magnetic properties is discussed. (orig.)