Carbon Dioxide Controlled Thermal-Decomposition Reactions for Preparation of High Quality YBCO Films Derived from Fluorine-Free Solution

摘要

We report the fabrication of high quality YBCO film through a carbon dioxide controlled thermal-decomposition reaction. During the pyrolysis process of the YBCO gel film, the low melting-point Ba(OH)_2 phase was converted to a high melting-point BaCO_3 phase when CO_2 was introduced into the heat treatment atmosphere, thus resulting in a quite smooth surface morphology of the pyrolyzed YBCO film; Then the BaCO_3 phase was converted to Ba(OH)_2 phase used as the Ba resource to produce the YBCO phase during the subsequent crystallization and annealing oxidation process. It is found that YBCO film with smooth surface and excellent superconductivity can be obtained through controlling the conversion reaction between the Ba-contained compounds by introducing adequate carbon dioxide and water vapor.