Hartmut Keune

MOCVD of YBCO and Buffer Layers on Textured Ni Alloyed Tapes

A RTR MOCVD was used for the deposition of YBCO and various oxides. A new MOCVD technique enable us to coat the metal tape directly without formation of NiO. At a low oxygen partial pressure the buffer layers were grown on the metal tape with good in plane and out of plane texture. The texture of the MgO buffer layers depend on the surface of the alloyed Ni-tape. YBCO layers exhibit excellent out of plane texture with FWHM(005) = 1.4 - 3.5deg and good in plane texture of FWHM(103) = 5-7deg. On MgO buffered Ni5at%W the inductive measured jc was 0.3-0.7 MA/cm2 at 77 K.

Electrically conducting oxide buffer layers on biaxially textured nickel alloy tapes by reel-to-reel MOCVD process

Reel-to-reel MOCVD process for continuous growth of electrically conducting buffer layers on biaxially textured Ni5W tapes has been developed. The new buffer layer architechture is presented: 200 nm (La, Ba)2CuO4/40 nm (La, Ba)MnO3/Ni5W. Constituting layers with high structural quality have been grown on moving tapes (in plane FWHM ≤ 6° and out of plane FWHM ≤ 3°).

MOCVD of coated conductors with electrically conductive buffer layers and their electrical field

A new MOCVD technique was developed for the deposition of oxides at a controlled low oxygen partial pressure, which enable to coat textured metal tapes with electrical conductive perovskites. In a RTR MOCVD-system metal tapes were coated with electrical conductive (La, Ba)MnO3, (La, Sr)MnO3, (La, Sr, Pb)MnO3 and (La, Ba)2CuO4 buffer layers and YBCO. In the same RTR-system YBCO was deposited on different buffered metal tapes. Computer calculations were used to characterise the behaviour for a weak superconducting part of a CC-tape with a conductive buffer layer system.