Abstract
The metastable A15 V3Al phase was obtained on glazed alumina (glass-coated alumina) and Au-coated sapphire substrates by sputtering using a composite target of Al and V. However, the metastable phase was not formed on sapphire or Ag-coated sapphire substrates. From the depth profile of the composition of the films prepared on glazed alumina substrates, it was found that Si and Ca atoms diffused into V–Al films from the glazed alumina substrate forming an A15 V3(Si, Ca) layer. The metastable A15 V3Al phase was grown self-epitaxially on such layers. The Tc value of the A15 V3Al prepared on glazed alumina substrates was higher than that prepared on Au-coated sapphire substrates. The maximum Tc of 13.8 K was obtained for the films prepared on glazed alumina substrates.