C-Axis Lattice Spacing Control of As-Grown Bi-Sr-Ca-Cu-O Thin Films by Single-Target Excimer Laser Ablation

Abstract

As-grown c-axis-oriented thin films of Bi-Sr-Ca-Cu-O on MgO(100) substrates were prepared by simultaneous deposition using the pulsed excimer laser ablation technique. The c-axis spacing of lattice planes could be controlled by the variation of Ca and Cu contents using simultaneous deposition with single targets. As Ca and Cu contents increased, the peaks of the X-ray diffraction pattern approached that of (Ca_0.86Sr_0.14)CuO₂; the n=∞ parent of the Bi₂Sr₂Ca _n-1Cu _n O _y superconductors with a lattice constant, 3.1995 Å, of the c-axis. After postannealing, films with T _c,end over 100 K were obtained.