Growth and superconducting properties of Bi₂Sr₂Ca₂Cu₃O₁₀single crystals

Abstract

Single crystals of Bi2Sr2Ca2Cu3O10 (Bi-2223) have been grown using the travelling solvent floating zone technique in an image furnace. Annealing the crystals under high pressures of O2 increased their critical temperature to 109 K, and resulted in sharp superconducting transitions of ΔTc = 1 K. The superconducting anisotropy of Bi-2223 was found to be , from measurements of the lower critical field with the magnetic field applied parallel and perpendicular to the c-axis. The anisotropy of Bi-2223 is significantly reduced compared to that of Bi2Sr2CaCu2O8 (Bi-2212), and this accounts for the enhanced irreversibility fields in Bi-2223. Furthermore, Bi-2223 has a higher critical current density, and a reduced magnetic relaxation rate compared to Bi-2212, which are both signatures of more effective pinning in Bi-2223 due to its reduced anisotropy.