Growth of high-quality Bi₂Sr₂CaCu₂O_z crystal and characterization

We report growth of high-quality Bi₂Sr₂CaCu₂O_z single crystals with dimensions 2 × 1 × 0.03 mm³ with a melt and growth technique. The composition of this crystal is homogeneous and very close to the stoichiometric composition. Structure characterization of a single crystal was realized by measuring the (001) x-ray diffraction. The lattice parameters of a typical crystal are a = 5.414(2) Å, b = 5.413(2) Å. and c = 30.823(10) Å. The superconducting temperature T_c = 95 K with a sharp transition width (10-90% level) between 6 and 10 K was determined from resistivity and dc susceptibility. We have measured the magnetization of Bi₂Sr₂CaCu₂O_z single crystal under magnetic field applied along the c-axis. The anomalous second peak effect appeared between 20 and 30 K. We discuss the qualities of these crystals.