Influence of Thickness on Performances of YBa$lt;inf$gt;2$lt;/inf$gt;Cu$lt;inf$gt;3$lt;/inf$gt;O$lt;inf$gt;7-δ$lt;/inf$gt; Films Prepared by Metal Organic Solution Deposition

Abstract

Trifluoroacetate metal organic deposition (TFA-MOD) is one of the most promising technology routes for fabrication of YBa2Cu3O7-δ (YBCO) coated conductors. In this paper, high-boiling point organic solvent diethanolamine (DEA) was added to modulate and to improve the properties of precursor solution by suppression the defect in the final films. And the thickness of single coated film was increased by increased concentration of the metal ions in the precursor solution. It is revealed that an exponential relationship was found between the thickness of precursor film after low-temperature decomposition and the ion concentration, as well as the viscosity of precursor solution vs the ion concentration. Optimizing the ion concentration and dip-coating parameters, smooth and crack-free YBCO films after crystallization are achieved with the thickness more than 1.3 μm. The films show homogeneous microstructures while dispersive heterogeneous particles appear in the surface of the thick films. Critical current density (Jc) measurement shows a decrease of Jc due to the increase of the thickness of YBCO films prepared by high concentration precursor solution, while critical currents (Ic) are distinctly improved. For instance, the Ic value of YBCO film prepared by 2.5 mol/L precursor solution is 4.7 times of that by 1.0 mol/L precursor solution. 1168 无 机 材 料 学 报 第 29 卷