Analysis of Thermodynamic Conditions for Formation of Single Phase in Bi-superconductor Thin Films

Bi 초전도 박막에서 단일상 형성을 위한 열역학 조건 분석

High quality BSCCO thin films have been fabricated by means of an ion beam sputtering at various substrate temperatures, $T_{sub}$, and ozone gas pressures, $PO_3$. The correlation diagrams of the BSCCO phases appeared against $T_{sub}$ and $PO_3$ are established in the 2212 and 2223 compositional films. In spite of 2212 compositional sputtering, Bi220l and Bi2223 phases as well as Bi2212 one come out as stable phases depending on $T_{sub}$ and $PO_3$. From these results, the thermodynamic evaluations of ${\Delta}H$ and ${\Delta}S$ S, which are related with Gibbs' free energy change for single Bi2212 or Bi2223 phase are performed.