High Tc Superconducting Bi-(Pb-)Sr-Ca-Cu-O Films Deposited by Pulsed Nd:Yag Laser Ablation

High To superconducting Bi-(Pb-)Sr-Ca-Cu-O thin films were ablated on MgO(l00) substrates at room temperature using a Nd:YAG laser at 1064 or 532 nm. The target materials had compositions near Bi2-xpbxSr2Ca2+yCu3+zOy (x<0.6, y,z<l) and their zero resistivity temperatures were 101 - 105 K. The amorphous films were crystallized either by annealing near 850°C or they were first melted and then annealed. The effects of laser ablation parameters and annealing conditions were investigated. The films were studied by XRD, SEM/EDS and resistivity measurements.The best films were annealed near 850 °C and they consisted mainly of the 2223 phase. These films had T9(midpoint) at 107 K and zero resistivity at 100 K. In the melt-treated films the amount of the 2223 phase as well as Tc was lower. The superconducting phases in the annealed films were strongly oriented with their c-axes perpendicular to the substrate surface.