Rapid annealing effect in the superconducting 2223 Bi(Pb)SrCaCuO thin films prepared by sputtering

Abstract

Thin films of Bi(Pb) SrCaCuO were prepared on MgO (100) by single-target sputtering. This deposition process yielded c-axis oriented superconducting thin films with a smooth surface. The as-grown films showed a 2223 single phase and zero resistivity at about 83 K. After deposition, the films were rapidly annealed at 830–850 °C within 120 s in air. The superconducting properties of the annealed films were greatly improved by optimizing the temperature and time during rapid annealing. The lead concentration in the as-grown films apparently was almost zero. However, the films annealed while placing a Bi(Pb)SrCaCuO bulk sample directly on the film surface had a clear lead concentration. The relative cationic ratio of the other elements in the annealed films was almost the same as that of the as-grown films. X-ray photoelectron spectroscopy measurement was carried out to study the change of chemical environments of each ion. Films annealed at 840 °C for 30 s in air showed zero resistivity at 105 K and had the critical current density of about 3×106 A/cm2 at 77 K.