Epitaxial Y1Ba2Cu3O7−x- and Y2Ba4Cu8O16−x-films using the BaF2-method

✍ Scribed by S. Dina; M. Moske; G.V. Minnigerode; K. Samwer

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 308 KB
• Volume: 165-166
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/s0921-4526(09)80333-5

✦ Synopsis

We have prepared epitaxial YlBa2Cu307"x -and Y2Ba4Cu8016-x-films on SrTi0 3substrates by simultanous evaporation of Y, Cu and BaF 2 followed by an ex situ thermal treatment. Varying the maximal annealing temperature (Tmax) results in a change of the structure and the electrical properties of the films from a nearly single phase "1,2,3"-structure with T c =92,1 K (Tmax =850°C) to a nearly single phase "2,4,8"-structure with T c =80,4K (T max =800oC).

("1,2,3"-phase: c=I,168±O,OOlnm). Due to the fact that both superconducting phases grow totally c-axis oriented on the SrTi0 3substrate only (OOi )-peaks are seen. For films deposited in the same way, as far as we can tell, a Tmax of 850°C produces reproducible "1,2,3"-phase films while T max = 800°C leads to the "2,4,8"-phase (see Fig. ). Although the films do not have the atomic ratio Y: Ba: Cu = I: 2: 3 but ratios between I: 1.35: 2.00 and