The effect of low oxygen partial pressure and high Pb-doping on Bi-2212 phase formation and flux pinning

• Published in: Physica. C, Superconductivity Vol. 314; no. 1; pp. 12 - 18
• Main Authors: Crossley, A.L., Li, Y.H., Caplin, A.D., MacManus-Driscoll, J.L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.1999
• Subjects: Bi-2212; Low pO 2 processing; Nanophases; Pb doping; Pinning; Superconductivity; Nanophases; 74.62.Dh; Superconductivity; 74.52.D; Pinning; Pb doping; Low pO 2 processing; Bi-2212; 74.72.Hs
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/S0921-4534(99)00036-2

Bi 2.2− x Pb x Sr 2Ca 1Cu 2O 8+ δ ((Bi,Pb)-2212) was prepared under different oxidising conditions in a coulometric titration (CT) system. The effect of oxygen partial pressure ( pO 2) and Pb doping on (Bi,Pb)-2212 phase formation has been explored using X-ray diffraction (XRD), electron dispersive analysis (EDS) and transition electron microscopy (TEM). Under reducing conditions, the Pb solubility in Bi-2212 was found to increase. For 0.4< x<0.6, nanosize particles of (Bi,Pb)-2212 were observed within the (Bi,Pb)-2212 matrix. The pO 2 dependence of Pb solubility within the (Bi,Pb)-2212 phase is discussed with reference to solubility limits of Pb and possible spinodal decomposition of (Bi,Pb)-2212. The effect of Pb-doping on the intragranular critical current within the bulk samples was explored using a vibrating sample magnetometer at a range of temperatures and J c was found to be enhanced by a factor of 4 above 40 K.