Amorphous phase separation in the metallic glasses ${\left({\mathrm{Pb}}_{1-y}{\mathrm{Sb}}_y\right)}_{1-x}{\mathrm{Au}}_x$

A novel family of ternary superconducting metallic glasses of the form ${\left({\mathrm{Pb}}_{1-y}{\mathrm{Sb}}_y\right)}_{1-x}{\mathrm{Au}}_x$ have been prepared by the method of melt quenching and studied by x-ray diffraction and electron microscopy. For $y=0.5\mathrm{} \mathrm{and} 0.25$, and $0.35<x<\mathrm{}0.7\mathrm{}$, measurements of superconducting properties suggest that these glasses are phase separated into two amorphous phases. X-ray-diffraction studies also suggest a phase separation. The two amorphous phases have been directly observed using electron microscopy and selected area electron diffraction. The scale of the domain structure is 1000-2000 Å. All of the superconducting properties measured can be understood in terms of the observed separation of amorphous phases.