CeO₂ Buffer Layers for HTSC by an Aqueous Sol‐Gel Method – Chemistry and Microstructure

Abstract

During the last decade the focus in superconductivity research has shifted towards the manufacturing of easy-to-handle superconductors, because of their high usability in electronic applications in comparison to bulky ceramics. This article reviews our recent progress made in the buffer-layer architecture of such a coated conductor, focusing on CeO 2 thin films prepared by an aqueous sol-gel method and deposited by dip-coating. Starting from water-soluble cerium(III) nitrate precursors, we were able to deposit films showing a very high degree of [002] orientation depending on the film characteristics and synthesis conditions. The formation and stability of the chemical complexes in the solu-

Aliovalent doping of CeO2: DFT study of oxidation state and vacancy effects

“…This latter aspect is of importance when perfect interfaces are required, and should be considered when crack formation in thin films is an issue. 16,17,19,21 …”

Influence of Morphology and Texture of CeO2 on YBa2Cu3O7 (YBCO) Growth and BaCeO3 Formation in Solution‐Derived Synthesis

“…[24] Well-studied ones are, for example, citric acid, ethylenediaminetetraacetic acid and nitrilotriacetic acid. [15,16,25] All of them are rather bulky ligands, thereby resulting in quite exothermic decomposition reactions throughout the formation of CeO 2 . Therefore, in this work we chose to use iminodiacetic acid (IDA) (log K1 = 6.18 and log K2 = 10.71) as a smaller ligand.…”

“…[19] As the thickness of the CeO 2 buffer layer is limited to approximately 70 nm before cracks are formed, [16] which is insufficient to avoid Ni x O y diffusion into the YBCO layer, La 2 Zr 2 O 7 is used as a thick (150-300 nm) extra buffer layer. This phase, on the other hand, has the tendency to form nanovoids throughout the layer thickness.…”

A new parameter in polymer - assisted sol - gel deposition of CeO2 thin film

“…На подложке всегда имеются дефекты, локально на-рушающие условие эпитаксии [5]. Так используемые частицы наноразмерны(~3-4 нм [6]), можно принять, что упавшая на недеформированный участок частица в ориентации (111) (предпочтительная ориентация частиц в золе, [2]) (неэпитаксиальная ориентация) в состоянии сменить ориентацию на (100) (эпитаксиальная ориен-тация), ибо с одной стороны энергия нескомпенсиро-ванного заряда поверхности частицы [3] (потенциал к ориентации в (111)), с другой -энергия нарушенных свя-зей (потенциал к ориентации в (100)).…”

“…В работе ответственным за образование неэпитаксиально ориентированных зерен CeO 2 счита-ется полуторный оксид Ce 2 O 3 , образующийся при не-достатке кислорода, -«минимальное рассогласование в параметрах кристаллических решеток при сопряжении CeO 2 с (0001) Ce 2 O 3 обеспечивается в том случае, когда (111) CeO 2 || (0001) Ce 2 O 3 ». В статье [5] пленки двуокиси церия получают золь-гель методом.…”