Superconducting Bi-Sr-Ca-Cu-O films prepared by laser ablation

Superconducting thin films of Bi-Sr-Ca-Cu-O have been grown on single crystal (100) SrTiO3 and MgO substrates using laser ablation at 355 nm. Films have been deposited using compositions of 2:2:1:2 (Bi:Sr:Ca) and 1.86:0.33:1.93:2.06:3.06 (Bi:Pb:Sr:Ca) to form primarily the low temperature Bi2Sr2Ca2Cu2Oy and the high temperature Bi2Sr2Ca2Cu3Ox phases, respectively. Films deposited at 760-765°C substrate temperature in the presence of 1 Torr of oxygen show superconducting onset temperatures of 85 K and 110 K, respectively, for the two compositions, with zero resistance obtained at about 70 K in both cases. The zero resistance temperatures for the films can be improved by subsequent annealing of the films at higher temperatures. © 1989 SPIE.