Thermal stability and annealing of columnar defects in Bi₂Sr₂Ca₁Cu₂O₈/Ag superconductor

Abstract

This work establishes the stability at elevated temperatures of columnar defects, artificially formed in the Bi-based cupric oxide superconductor Bi₂Sr₂Ca₁Cu₂O₈ for enhanced vortex pinning. Isochronal anneals, conducted in air, led to losses of critical current density in two stages. The defects were relatively stable up to ~ 550 °C, where second stage annealing began; above this, the pinning diminished rapidly. The recrystallization and loss of columnar defects were corroborated by transmission electron microscopy.