Low-Temperature Growth of High-Tc Bi-Sr-Ca-Cu-O Films by Magnetron Sputtering

Superconducting thin films of Bi-Sr-Ca-Cu-O have been grown on heated MgO, sapphire, and SrTiO3 substrates by magnetron sputtering. For films grown at substrate temperatures between 560–600°C, T c onset behavior above 110 K was observed. These films contain a phase having a c-axis lattice parameter, c 0, of 36.83 A in coexistence with a phase having c 0 of 30.67 A. These as-grown films show zero resistence at 56 K. Zero resistence of 90 K was achieved in postannealed films on MgO. A thin-film growth method like sputtering is capable of stabilizing the 110 K phase in the Bi-Sr-Ca-Cu-O system at low growth temperatures below 600°C.