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Bi2Sr2CaCu2Ox(Bi-2212)薄膜制备工艺相对简单,在低温下具有优异的性能,因此备受青睐,已经有不少研究小组采用真空或非真空方法成功制备出高质量的Bi-2212薄膜。一般而言,单晶基底被广泛用于Bi-2212薄膜的制备。与单晶基底不同,银基底无织构,但银基底的表面粗糙度等因素对Bi-2212的c轴织构和临界电流密度有影响。并且由于银基底对Bi系高温超导材料具有较低表面能,因此Bi-2212薄膜可以在银基底上稳定存在。以乙酸-氨水溶液为基础,开发了一种在银基底上制备Bi-2212薄膜的方法,对其中的关键步骤做了详细的研究,主要包括银基底的抛光、化学溶液的配制、烧结温度等。重复旋涂-热解过程可以消除经由一次旋涂热解带来的气泡;另外在银基底和低氧分压条件下,Bi-2212的成相温度点下移,在790℃保温5 h即可制备出单相Bi-2212薄膜。扫描电镜(SEM)观测表明,薄膜表面均匀平整无裂纹。随着烧结温度的升高,Bi-2201相开始出现并且其衍射峰的强度随烧结温度的升高迅速增加;当烧结温度为850℃时,出现了一种棒状相,能谱(EDS)分析表明该棒状相是一种缺Cu相。
Bi2Sr2CaCu2Ox (Bi-2212) thin film preparation process is relatively simple, has excellent performance at low temperatures, therefore, has been favored, many research groups have been successfully prepared using vacuum or non-vacuum high-quality Bi-2212 film. In general, single crystal substrates are widely used for the preparation of Bi-2212 thin films. Unlike single crystal substrates, the silver substrate has no texture, but the surface roughness of the silver substrate and other factors have an influence on the c-axis texture and the critical current density of the Bi-2212. And the Bi-2212 thin film can be stably present on the silver substrate because the silver substrate has a lower surface energy for the Bi-based high-temperature superconducting material. Based on the acetic acid-ammonia solution, a method of preparing Bi-2212 thin film on silver substrate has been developed. The key steps of the method have been studied in detail, including the polishing of silver substrate, the preparation of chemical solution, the sintering temperature and so on . The repeated spin-coating-pyrolysis process can eliminate the bubble caused by one spin-coating pyrolysis. In addition, under the conditions of silver substrate and low oxygen partial pressure, the phase transition temperature of Bi-2212 is shifted down and kept at 790 ℃ for 5 h Can be prepared single-phase Bi-2212 film. Scanning electron microscopy (SEM) observations show that the film surface is smooth and crack-free. With the increase of the sintering temperature, the phase of Bi-2201 began to appear and the intensity of its diffraction peak rapidly increased with the increase of the sintering temperature. When the sintering temperature was 850 ℃, a rod-shaped phase and EDS analysis Indicating that the rod phase is a lack of Cu phase.