Superconducting Bi-Ca-Sr-Cu oxide thin films by spray pyrolysis of metal acetates

Abstract

Superconducting Bi-Ca-Sr-Cu oxide thin films have been prepared on ZrO2-coated silicon (111) wafers by spray pyrolysis of metal acetate precursors followed by rapid annealing to 850 °C in air. Resistivity measurements indicate a broad superconducting transition with Tc onset near 90 K and zero resistivity below 60 K. The films are highly oriented with the c axis normal to the substrate surface and can be indexed to a tetragonal structure with lattice parameters of a=3.832(1) Å and c=30.78(5) Å. Both x-ray photoelectron spectroscopy and x-ray diffraction measurements indicate the loss of Ca to the ZrO2 buffer layer.