NUCLEAR AND MAGNETIC SHORT-RANGE ORDER IN (REXZR1-X) AMORPHOUS-ALLOYSCONTAINING HYDROGEN (RE = Y, TB, X = 0.65, 0.67)

The amorphous alloys (Y0.65Zr0.35)H0.45 and (Tb0.67Zr0.33)H0.46 have b een studied by neutron diffraction at room and low temperatures down t o 1.6 K. The experimental pair correlation functions lead to interatom ic distances of first neighbours and atomic and magnetic coordination numbers. The nuclear order of Y and Th alloys are shown to be similar; the atomic distribution is very close to a statistical accounting for composition and size of ions. The magnetic order, which is governed b y the anisotropy, is characterized by a rather small angle between the first moments indicating a relatively weak anisotropy. The comparison of the properties of quenched or sputtered Tb0.65Cu0.35 with those of the Zr alloy shows that for the Zr alloy the nuclear order is more re gular when the anisotropy and the negative RKKY interactions are less strong. These differences are more likely due.to the electronic struct ures of component ions and to the presence of hydrogen rather than to a particular atomic order.