Phase Evolution by Annealing in V/Al Multilayers Prepared on Thermally Oxidized Si

抄録

Phase evolution by solid-state reactions in Al/V multilayers ion-plated on thermally grown SiO₂ substrates was investigated by means of X-ray diffraction and transmission electron microscopy, and the possibility for the formation of superconducting phases of V₃Al and V₃Si with the A15 type structure was examined. Annealing at a temperature below about 973 K caused interdiffusion between V and Al layers resulting mainly in a solid-solution of Al in V. After annealing for 1 h at a temperature higher than about 973 K, several compounds were found to form by the reactions between the V–Al solid solution and SiO₂ substrate; A15-V₃Si, unidetified phase which was assumed tentatively as V_xO, and γ-Al₂O₃. The V₃Si phase was nucleated in the amorphous SiO₂ substrate at about 973 K, and grew markedly as the annealing temperature increased up to about 1223 K, but no indications for the formation of the metastable A15-V₃Al phase were detected.