Regulation of the Growth Orientation of Bi-2212 Thin Film and the Corresponding Influences on Critical Current Density

Bi2Sr2Ca1Cu2O8+σ (Bi-2212) superconducting thin films were prepared using the sol–gel method on a LaAlO3 (LAO) single crystal substrate. The influences of oxygen content in the process of heat treatment on the orientation degree and superconducting performance of the Bi-2212 films are discussed, and the results show that changing the oxygen content in a mixed atmosphere during the high-temperature heat treatment process could control the growth orientation of the Bi-2212 films. When the oxygen content was in a range from 0.5 to 2.0%, with an increase in oxygen content, the c-axis growth orientation degree of the thin film presented a linear growth trend, but if the oxygen content was too high in the atmosphere, it could lead to the generation of impure phases. Further study found that both Tc and Jc of the film increased with an increase in the c-axis orientation degree. Among different oxygen contents, when the oxygen content in the atmosphere was 2.0%, the prepared sample had good biaxial texture, compact surface structure, and a regular atomic arrangement; the corresponding c-axis orientation degree could reach 97%, and the values of Tc and Jc were 85.3 K and 4.46 × 105 A/cm2, respectively.