Transmission electron microscopy analysis of a coated conductor produced by chemical deposition methods

Behavior of oxygen diffusion in buffer layers for coated conductors

“…It indicates that the destruction of (0 0 l) orientation LZO film is not beneficial to the transfer of the biaxial texture of NiW substrate to the superconducting layer after annealing in oxidization atmosphere because of the oxidation of NiW substrates. It means that about 70 nm thick LZO films are not able to effectively prevent diffusion of oxygen into NiW substrates during 900 • C high-temperature processing even in a low oxygen partial pressure [15]. Furthermore, during annealing in oxidation atmosphere, it is highly possible that the nucleation of oxides related to Ni and W occurs first at the interface between LZO layer and NiW substrate and the growth front develops from the interface between LZO layer and NiW substrate to the surface of buffer layer.…”

“…NiWO 4 and NiO layers between buffer and substrate could easily form if the YBCO layer underwent a heat treatment with a long duration at high temperature during preparation of the YBCO superconducting layer by TFA-MOD method even if the oxygen partial pressure was only Ar-0.1% O 2 . These NiWO 4 and NiO layers consist of many small crystals with random orientations [15]. Therefore, we could suppose that there exist these kinds of oxide layers in the CeO 2 /NiW and CeO 2 /LZO/NiW samples annealed in oxidation atmosphere.…”

“…For the 70-nm thickness single LZO layer, its lower 30 nm is disturbed due to the oxidation of substrate, but its top 30 nm remains good biaxial texture after YBCO deposition. And on NiW substrate, NiWO 4 , NiO and LZO layers are detected in sequence [15]. Here 70 nm thick LZO films with good biaxial texture are obtained by MOD, but NiWO 4 and NiO phases are detected on the surface of the samples after annealing in oxidation atmosphere.…”

“…The procedures, which La 2 Zr 2 O 7 (LZO) and CeO 2 textured thin films are prepared on YSZ (yttria-stabilized zirconia) (0 0 l) single crystal substrates and textured NiW substrates by MOD, are well controllable and rather mature [7][8][9][10][11][12][13][14][15]. In addition, there exists large difference between the intrinsic oxygen diffusion coefficient of LZO and that of CeO 2 [13,16].…”

A study of the parameters influencing the microstructure of thick La2Zr2O7 films

“…In previously presented research [23,24], we developed thin LZO layers of 40 nm thick. The crystallinity, texture and morphology of the thin films was investigated.…”