NEUTRON-SCATTERING STUDY OF ATOMIC LOCAL ORDER IN AMORPHOUS TBXSI1-X (X=0.87, 0.59, 0.18)

Neutron scattering determination of the total structure factors of the amorphous Tb//xSi//1// minus //x system has been performed for three compositions in order to determine the atomic arrangement and the evolution of the local order as a function of the silicon content. Comparison has been made with a conventional structural model consisting of a binary mixture of hard spheres of different diameters. Total pair correlation functions have been determined. We propose a model for the local order around both the terbium and the silicon atoms which is in reasonable agreement with the physical properties of the system.