Choice of insulating layer for YBCO in a multilayer architecture on buffered RABiTS

The choice of insulating layer for a YBCO/insulator multilayer architecture on buffered RABiTS was investigated. Double YBCO layers separated by SrTiO3 (STO) insulating layers were deposited by PLD. The STO architecture exhibited a high T-c, small transition width and small out-of-plane and in-plane FWHM values. From surface morphology and microtextural analysis of STO/YBCO multilayer architecture, no high- angle grain boundaries were observed and most of the grains were well connected by boundaries with a misorientation of less than 10 degrees. Scanning transmission electron microscopy ( STEM) was further used to show that the interfaces of STO/YBCO/STO/YBCO on buffered NiW were clean and sharp. No chemical diffusion was observed between any interfaces and YBCO layers grew epitaxially. SrTiO3 is shown to be a good candidate to separate YBCO layers in a multilayer architecture for the coated conductor cylinder approach and the replacement of thick YBCO single layers for conventional tapes.