A Simple Technique to Prepare High Quality Superconducting Bi-Sr-Ca-Cu-Oxide Thin Films

Abstract

The discovery of high transition temperature superconductors as bulk ceramics^1,2 and subsequently the development of techniques to grow these materials as thin films³ has opened up different areas of possible applications at working temperatures above 77 K. The study of thin films of compounds with high T_C is important for both, fundamental physics as well as applications. One first, large scale application of the new high T_C materials is expected to be in thin film devices like SQUIDs, wiring interconnections in conventional devices and some new device types interfacing semiconductor and superconductor systems. Consequently, the development of techniques facilitating a large scale production of films with reproducible physical properties is of major importance. The rare earth free Bi-Sr-Ca-Cu-Oxide (BSCCO) superconductor system is a good candidate for economic large scale applications due to its ease of thin film preparation and chemical stability. The discovery of the Bi-Sr-Ca-Cu-Oxide system with several superconduct ing phases ^4–6 generated much fundamental as well as practical interest. It was readily seen that at least two superconducting phases of this compound exist with critical temperatures of 85 K, and 110 K, respectively.Structural analysis of these compounds shows that the occurrence of CuO planes in an unit cell is associated with the high critical temperature, the number of CuO planes is proposed to be correlated with the critical temperatures.⁷