XANES spectra of mechanical alloyed Y-Cu system

We report changes in the structure and the electronic states of YCu2 during mechanical alloying. The x-ray diffraction shows that milling for about 60 h transforms mixture of elemental powders of Y and Cu into an amorphous alloy. We have measured the x-ray absorption near edge structure (XANES) spectra of mechanically alloyed YCu2 at Cu K and Y K edges at various milling time. The pre-edge peak near the Cu K threshold grows remarkably and its central energy decreases with increasing the milling time. The absorption near the Y K threshold, on the other hand, decreases with milling time. We discuss these features of XANES spectra in connection with the phase transformation from the crystalline to amorphous states.