Superconductivity of Ta-Zr films produced by co-sputtering

Using the phase spread deposition technique, thin films of Ta1-xZrxhave been prepared over a wide range of composition. We find a maximum superconducting transition temperature of 8 K, but only over a narrow range of deposition temperatures. Tunnel junctions form reliably at all Zr concentrations. X-ray analysis indicates that the bcc Ta phase extends to much higher Zr content than expected from the bulk phase diagram.