温度控制织构金属基带上YBCO外延薄膜生长及缺陷研究  

Effect of Substrate Temperature and Dislocation Density on the Epitaxial Growth of YBCO Thin Films on Textured Metal Tapes

作　　者：徐亚新[1] 熊杰[1] 夏钰东[1] 张飞[1] 薛炎[1] 陶伯万[1] 

机构地区：[1]电子科技大学电子薄膜与集成器件国家重点实验室,成都610054

出　　处：《无机材料学报》2013年第5期491-496,共6页Journal of Inorganic Materials

摘　　要：采用直流溅射法在Y2O3/Y S Z/C e O2(Y Y C)缓冲层的织构N i W基带上,通过基片温度调制YBa2Cu3O7-δ(YBCO)外延薄膜生长。X射线衍射仪(XRD)表征显示,基片温度强烈地影响YBCO薄膜的外延生长:在较低的基片温度下薄膜趋于a轴取向生长,随基片温度升高薄膜逐渐变为纯c轴取向生长。由于a轴晶粒引起的大角度晶界会阻碍超导电流在a-b面内的传输,因此YBCO薄膜的微观结构和超导电性能随温度升高而得到改善,但是随着基片温度继续升高,基带的氧化程度加剧,YBCO与缓冲层间发生界面反应,从而导致薄膜质量衰退。本研究还计算了YBCO薄膜中的位错密度,并研究了位错密度与自场下YBCO薄膜临界电流密度(Jc)之间的关系。结果表明:YBCO薄膜在自场下的临界电流密度对螺旋位错密度比对刃型位错密度更加敏感,这主要是由YBCO薄膜的螺旋生长机制引起的。Epitaxial YBa2Cu3O7-6 （YBCO） thin films were grown on Y2O3/YSZ/CeO2 （YYC） buffered Ni-5at%W substrates by direct-current sputtering, and induced by substrate temperature. X-ray diffraction （XRD） results showed that the substrate temperature strongly influenced the epitaxial growth of YBCO films： the a-axis preferential grains grew at lower substrate temperature, and strictly c-axis epitaxial YBCO films were achieved at higher substrate tem- perature. The amount of a-axis YBCO component evaluated from the ratio of XRD Z-scan integrated intensity of the a-axis and c-axis for the YBCO （102） plane decreased as the substrate temperature increased. Since the development of the a-axis component can result in high angle grain boundaries, which can degrade the Ic passing through the a-b plane, the microstructure and the critical current density of YBCO thin films were improved as substrate temperature increasing. While the microstructure and the critical current density of YBCO thin films were deteriorated above 780℃ for the baseband oxidation and the interface reaction between the YBCO and the buffer layer. The dislocation density in the YBCO thin films was measured and calculated. The relationship between the dislocation density and critical current density （Jc） was systematically investigated, Jc was much more sensitive to the screw dislocation than to the edge dislocation, which was attributed to the spiral growth mechanism of YBCO thin films.

关 键 词：YBa2Cu3O7-δ(YBCO) 基片温度 生长取向 位错密度 

分 类 号：TM26[一般工业技术—材料科学与工程]