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AuTa3 crystallizes in the cubic Pm-3n space group. The structure is three-dimensional. Ta is bonded in a 6-coordinate geometry to two equivalent Ta and four equivalent Au atoms. Both Ta–Ta bond lengths are 2.62 Å. All Ta–Au bond lengths are 2.93 Å. Au is bonded to twelve equivalent Ta atoms to form a mixture of edge and face-sharing AuTa12 cuboctahedra.
The characteristics of thin films of Ta-Cu, prepared over a wide range of compositions by cosputter deposition onto GaAs and fused quartz substrates, are studied by X-ray diffraction and van der Pauw resistivity measurement. Results show films to be amorphous over the range of 55-95 at. pct, and show Ta(93)Cu(7) barriers to be effective in preventing Au in-diffusion, with a 3000-A layer remaining unpenetrated after an annealing at 700 C for 20 min. Diffusion of Ga and/or As into amorphous 93 at. pct Ta is found to be more rapid than that of Au, and interfacial reactions were shown to form compounds including Ta3Au, CuAu, TaAs2, and Ga3Cu7 above 700 C.