为了探讨低氟前驱液对应的低温热解过程的升温速率对超导膜YBazCusO7-δ(YBCO)表面形貌和超导性能的影响,我们在不同的低温热解速率下(1,3,5,10,15,20℃/min)制备了一系列的超导膜.低氟前驱液中的氟含量比全氟前驱液中减少了大约50%.X光衍射(XRD)分析表明:采用低氟前驱液,在很大的升温速率窗口,都能容易地获得良好外延生长的YBCO超导薄膜.但是,过快的热解速率(如15、20℃/min),会导致超导膜表面的恶化,出现皱褶或裂纹.升温速率在1℃/rain和10℃/min之间,自场下的临界电流密度(Jc)能保持比较高的值.在当前实验条件下,考虑YBCO超导膜的综合性能,5℃/min是最合适的低温热解速率.采用低氟前驱液,在5℃/min,600nm的YBCO膜的低温热解时间可以缩短到50分钟,其样品织构良好、表面平整;在LaAlO3单晶上制备的200nm的YBCO膜可以获得Jc为3.0MA/cm2左右(77K,自场).
To investigate the influence of pyrolysis heating rate on the microstructure and transport properties of YBaz Cu3 O7-δ (YBCO) films deposited by the low-fluorine (LF) process, the films have been prepared at a series of heating rates (1, 3, 5, 10, 15, 20 ℃/min). The total content of fluorine in LF solution is reduced about 50% of that in the All-TFA solution X-ray θ--2θ diffraction (XRD) analysis shows that the epitaxial growth of YBCO superconducting films using the LF solution is easy to form at large rate range. But the rapid pyrolysis rates (such as 15, 20 ℃/rain) have caused wrinkles on the surface of the films. The critical current density (Jc) values in self- field are better at the heating rates between 1 ℃/min and 10 ℃/min. Considering the comprehensive performance of YBCO superconducting films, 5 ℃/min is the most suitable rate under the current experimental conditions. The 600 nm YBCO films show smooth surface and well texture at 5 ℃/min,. The Jc of the YBCO films with thickness of 200 nm reaches 3.0 MA/cm2 (77 K, self-field) on the LaA1O3 at pyrolysis rate 5 ℃/mirL