LARGE-AREA DEPOSITION OF BIAXIALLY TEXTURED YSZ BUFFER LAYERS USING AN IBAD-PROCESS

An ion-beam-assisted deposition technique (IBAD), using two Kaufman io n sources with diameters of 11 cm, was employed to grow biaxially text ured YSZ buffer layers. They serve as a template for YBCO films and as a diffusion barrier. The best YSZ films on small Al2O3 substrates sho w good in-plane alignment characterized by a FWHM of 10.8 degrees in ( 111)-Phi-scan. An improvement of texture with rising film thickness wa s observed saturating at 8.5 degrees. On 100 cm(2) large substrates th e texture was within a range of 15 degrees to 24 degrees. First improv ements of the homogeneity were achieved by a four-time rotating of 90 degrees of the substrate holder around the substrate normal during dep osition. On polycrystalline PSZ substrates with YSZ buffers YBCO films with a critical current j(c) > 10(6) A/cm(2) (at 77 K, 0 T) were depo sited.