热处理温度对MOD-YBCO薄膜微结构和超导电性的影响

Effect of Fired Temperature on Microstructure and Superconductivity of MOD-YBCO Thin Films

采用TFA-MOD法在LaAlO3基体上制备YBCO薄膜,热处理温度为780-860℃。XRD结果表明,热处理温度在780-820℃之间时,随着热处理温度的提高,YBCO薄膜中BaF2逐渐减少,a轴生长的晶粒和杂质相减少,c轴生长的晶粒增加;热处理温度在820-860℃之间时,随着热处理温度的升高,薄膜中a轴生长的晶粒增加,c轴生长的晶粒减少;SEM分析发现,YBCO薄膜表面较平整,无裂纹;超导性能测试结果表明,热处理温度为820℃的YBCO薄膜的临界电流密度Jc可达1 MA.cm^-2（77 K,0 T）。

Epitaxial YBCO superconducting thin films were prepared by metal organic deposition （TFA-MOD） method on single crystalline LaAlO3（001） substrate and adopting heat treatment temperature was in the range of 780 - 860 ℃, and mierostrueture and superconductivity of YBCO thin films were characterized by means of scanning electron microscope （SEM） and Jo-scan system. X- ray diffraction method （XRD） results showed that with the temperature rising BaF2 in the films decreased and the grains grown in c-axis orientation of texture in-creased, but that in a-axis orientation and impurity phases decreased as the temperature was within 780 - 820 ℃ ; as the temperature was within 820 - 860 ℃, with the temperature increasing the grains grown in c-axis orientation of texture decreased and that in a-axis increased. From SEM observation of the YBCO films it was found that the surface of the film was smooth and without micro crack. The result of testing superconducting property showed that J o value of the YBCO film treated at 820 ℃ was 1 × 10^6 A·cm^-2 at 77 K, in self-field.