Deposition of YBCO thin films over large areas by a 90° off-axis sputtering technique

Abstract

We report the deposition of YBCO thin films with uniform thickness (87.5 K) and critical current density (J/sub c/ /sub 77/ /sub K/>1/spl times/10/sup 6/ A/cm/sup 2/, J/sub c/ /sub 4.2/ /sub K/>1/spl times/10/sup 7/ A/cm/sup 2/) over an 8" diameter area. Considering only the better optimized samples the films displayed high critical current densities (J/sub c/ /sub 77 K/ >3/spl times/10/sup 6/ A/cm/sup 2/, J/sub c/ /sub 4.2 K/ >3/spl times/10/sup 7/ A/cm/sup 2/). The variations in the film properties have been correlated to the variations in crystalline quality, amount of c-axis grains and substrate temperature during deposition.