Abstract
Single crystals of the superconductor with the composition, Bi2.2Sr1.8 Ca1.0Cu2.0 O8.2, were grown by the travelling solvent floating zone method with changing the oxygen partial pressure, PO2, and measurements of physical properties were carried out. Stabilization of molten zone during the crystal growth can easily be attained with feed rods which were uniformly densified by a quick zone-pass. Oxygen partial pressures from 22 to 100kPa do not show any effect on the crystal size nor the formal charge of Cu ions. Density measurement suggests the coexistence of cation defects and excess anion oxygen. Zero resistance temperature, Tc, is 83K in case of crystals grown at PO2=22, 60 and 100kPa, while 57K at PO2=0kPa. Magnetization hysterisis loops in the applied field, H, parallel to the c-axis at 4.3K show that the critical current density, Jc, is insensitive to the applied field, indicating a large pinning potential in the single crystal. By the bean model a value of Jc is estimated as 2.5×106A/cm2 at 4.3K and 0 Oe for the crystal grown at PO2=100kPa.
