Investigation of TiN Seed Layers for RABiTS Architectures With a Single-Crystal-Like Out-of-Plane Texture

Abstract

Sharpening of the substrate texture is key to obtain critical current densities approaching single crystal values in coated conductors. In particular, great improvements in J/sub c/ are obtained by narrowing the substrate texture down to values of 3-4/spl deg/ for both phi-scan and omega-scan FWHM. The best Ni-alloy substrates used today for RABiTS show FWHM's of 6-5/spl deg/. Although the majority of buffer layers deposited on these tapes by various techniques approximately duplicate the substrate's grain alignment, some materials have been found to develop much sharper out-of-plane texture. Here we report on growth and structural characterization of TiN seed layers on various textured metal tapes. TiN seed layers deposited by PLD have consistently shown tilting of the c-axis toward the direction of the sample's surface normal. We address the extent of such tilt and discuss feasibility of alternative RABiTS architectures that use a TiN seed layer to provide very sharp out-of-plane texture and serve as an effective metal-ion diffusion barrier.