X射线三晶衍射研究YBa_2Cu_3O_y超导薄膜

X-RAY TRIPLE AXIS SCATTERING STUDIES OF YBa_2Cu_3O_y SUPERCONDUCTING THIN FILM

应用X射线三晶衍射对LaAlO_3衬底上生长的YBa_2Cu_3O_y薄膜中的应力水平、存在的主要缺陷,以及薄膜与衬底的失配和取向关系等进行了研究。结果表明,薄膜在衬底上几乎完全松弛,应力很小,薄膜存在较严重的晶格取向差缺陷,这是影响薄膜晶体结构完整性的主要因素。此外,衬底与薄膜在垂直于表面和平行于表面方向都存在取向差。

The YBa2Cu3Oy thin film on LaAlO3 substrate was investigated by triple axis scattering. Stress, main defects in the film and the crystallographic relationship between the thin film and substrate were studied. Experimental results show that the thin film on substrate was slmost totally relaxed and very low strain and stress existed in the film. The film behaves as a 'free' bulk layer on the subtrate. The larger mosaic width of the film indicates the film has poor crystallinity and includes a lot of lattice misorientation defects. Misorientations between the film and substrate were observed in both the perpendicular and parallel direction of the surface.