直流溅射法制备YBCO带材研究
发布时间：2018-07-28 15:04
【摘要】： YBCO高温超导带材具有优异的电学性能,它具有在外场下临界电流高,交流损耗低以及成本较低等优点,在工业应用中有非常大的潜力,所以各国都投入了巨大的人力物力进行研究。直流溅射具有方法简单、易于控制以及工艺重复性好等特点,本文基于直流溅射法研究了Y2O3种子层薄膜的制备工艺,并且在制备有Y2O3/YSZ/CeO2 (YYC)缓冲层的镍钨合金(Ni-5at.%W)基带上制备YBCO涂层导体进行了研究,还对YBCO薄膜的磁通钉扎特性也做了初步探讨。主要内容如下: 1、根据c轴择优度和温度的关系以及反应溅射特有的迟滞效应,得出当温度为720℃,溅射电流为0.2A,水分压为0.016Pa,反应溅射处于平衡状态,制备出Y2O3种子层薄膜纯c轴取向,且面内面外半高宽为3.9°和4.9°。 2、在Y2O3/YSZ/CeO2(YYC)缓冲层上制备YBCO涂层导体,发现缓冲层表面粗糙度对YBCO薄膜的性能有很大的影响,分别在反应溅射法和射频溅射法制备YYC缓冲层上以相同的工艺制备YBCO薄膜,两种缓冲层都是纯c轴取向,面内面外取向一致性相当,但反应溅射法制备的缓冲层粗糙度明显大于射频溅射制备的,在前者上制备的YBCO薄膜临界电流密度Jc为1.2 MA/cm2,而在后者基础上制备的YBCO薄膜的临界电流密度Jc达到2.8 MA/cm2。 3、探讨了用卷绕法在平面靶直流溅射装置上连续制备YBCO带材的工艺,780℃为卷绕法制备YBCO薄膜的适宜温度,由于平面靶的负离子反溅射效应较为明显,综合考虑靶基距和气体总压,并且通过改变卷绕速度,补偿由于负离子反溅射效应导致的成分偏差,在靶基距为20mm,气体总压为70Pa,卷绕速度为0.55m/h时,临界电流密度达到0.6MA/cm2。 4、研究了YBCO超导薄膜在磁场下的性能变化,首先在65K和77K的温度下,外加0-2T的磁场下对未掺杂的YBCO薄膜的性能进行测试,磁场方向垂直于基片表面,温度越低,YBCO薄膜的性能随磁场强度的增大下降的趋势越弱,然后我们还用Y过量的靶制备了富Y的YBCO薄膜,由于Y2O3在YBCO薄膜中形成钉扎中心,其在磁场下的性能明显优于未掺杂的YBCO薄膜。
[Abstract]:YBCO high temperature superconducting strip has excellent electrical properties. It has the advantages of high critical current, low AC loss and low cost in external field. It has great potential in industrial application. So many countries have invested huge manpower and material resources to study. DC sputtering has simple method, easy control and good process repeatability. In this paper, the preparation process of Y2O3 seed layer films was studied based on DC sputtering, and the preparation of YBCO coated conductors on the base band of nickel tungsten alloy (Ni-5at.%W) with Y2O3/YSZ/CeO2 (YYC) buffer layer was studied. The magnetic flux pinning properties of the YBCO film were also discussed. The main contents are as follows:
1, according to the relationship between the optimum degree and the temperature of the c axis and the specific hysteresis effect of the reactive sputtering, it is obtained that when the temperature is 720, the sputtering current is 0.2A, the water pressure is 0.016Pa and the reactive sputtering is in the equilibrium state, the pure c axis orientation of the Y2O3 seed layer film is prepared, and the outer surface half width of the surface is 3.9 and 4.9 degrees.
2, to prepare the YBCO coated conductor on the Y2O3/YSZ/CeO2 (YYC) buffer layer, it is found that the surface roughness of the buffer layer has a great influence on the performance of the YBCO film. The YBCO film is prepared by the same process in the reaction sputtering and the RF sputtering preparation of the YYC buffer layer respectively. The two buffer layers are pure c axis orientation, and the in-plane orientation consistency is equal, but it is quite consistent. The roughness of the buffer layer prepared by reactive sputtering is obviously greater than that of RF sputtering. The critical current density of the YBCO film prepared on the former is 1.2 MA/cm2, while the critical current density of the YBCO thin film prepared on the basis of the latter reaches 2.8 MA/cm2..
3, the process of continuous preparation of YBCO strip on a DC sputtering device by a winding method is discussed. The suitable temperature of YBCO film is prepared by winding method at 780 C. Because the negative ion sputtering effect of the plane target is more obvious, the target base distance and the total gas pressure are taken into consideration, and the negative ion sputtering effect is compensated by the change of the winding speed. The composition deviation is caused by a critical current density of 0.6MA/cm2. when the target base distance is 20mm, the total gas pressure is 70Pa, and the winding speed is 0.55m/h.
4, the performance changes of the YBCO superconducting film under the magnetic field are studied. First, at the temperature of 65K and 77K, the performance of the undoped YBCO film is tested under the magnetic field of the 0-2T. The direction of the magnetic field is perpendicular to the surface of the substrate. The lower the temperature is, the weaker the performance of the YBCO film decreases with the increase of the magnetic field strength, and then we also use the target of Y excess. The Y rich YBCO thin films were prepared. Because Y2O3 forms a pinning center in YBCO films, its performance in magnetic field is much better than that in undoped YBCO films.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TM26
本文编号：2150625
[Abstract]:YBCO high temperature superconducting strip has excellent electrical properties. It has the advantages of high critical current, low AC loss and low cost in external field. It has great potential in industrial application. So many countries have invested huge manpower and material resources to study. DC sputtering has simple method, easy control and good process repeatability. In this paper, the preparation process of Y2O3 seed layer films was studied based on DC sputtering, and the preparation of YBCO coated conductors on the base band of nickel tungsten alloy (Ni-5at.%W) with Y2O3/YSZ/CeO2 (YYC) buffer layer was studied. The magnetic flux pinning properties of the YBCO film were also discussed. The main contents are as follows:
1, according to the relationship between the optimum degree and the temperature of the c axis and the specific hysteresis effect of the reactive sputtering, it is obtained that when the temperature is 720, the sputtering current is 0.2A, the water pressure is 0.016Pa and the reactive sputtering is in the equilibrium state, the pure c axis orientation of the Y2O3 seed layer film is prepared, and the outer surface half width of the surface is 3.9 and 4.9 degrees.
2, to prepare the YBCO coated conductor on the Y2O3/YSZ/CeO2 (YYC) buffer layer, it is found that the surface roughness of the buffer layer has a great influence on the performance of the YBCO film. The YBCO film is prepared by the same process in the reaction sputtering and the RF sputtering preparation of the YYC buffer layer respectively. The two buffer layers are pure c axis orientation, and the in-plane orientation consistency is equal, but it is quite consistent. The roughness of the buffer layer prepared by reactive sputtering is obviously greater than that of RF sputtering. The critical current density of the YBCO film prepared on the former is 1.2 MA/cm2, while the critical current density of the YBCO thin film prepared on the basis of the latter reaches 2.8 MA/cm2..
3, the process of continuous preparation of YBCO strip on a DC sputtering device by a winding method is discussed. The suitable temperature of YBCO film is prepared by winding method at 780 C. Because the negative ion sputtering effect of the plane target is more obvious, the target base distance and the total gas pressure are taken into consideration, and the negative ion sputtering effect is compensated by the change of the winding speed. The composition deviation is caused by a critical current density of 0.6MA/cm2. when the target base distance is 20mm, the total gas pressure is 70Pa, and the winding speed is 0.55m/h.
4, the performance changes of the YBCO superconducting film under the magnetic field are studied. First, at the temperature of 65K and 77K, the performance of the undoped YBCO film is tested under the magnetic field of the 0-2T. The direction of the magnetic field is perpendicular to the surface of the substrate. The lower the temperature is, the weaker the performance of the YBCO film decreases with the increase of the magnetic field strength, and then we also use the target of Y excess. The Y rich YBCO thin films were prepared. Because Y2O3 forms a pinning center in YBCO films, its performance in magnetic field is much better than that in undoped YBCO films.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TM26
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