Phase development of Bi-2212 superconductor: A time-resolved neutron powder diffraction investigation

Abstract

Time-resolved in situ neutron powder diffraction and Rietveld refinement have been used to study the synthesis of Bi-2212 from hydroxide precursors in a 2% O2 atmosphere. Bi-2212 was found to form within the temperature range 770–800 °C. Studies at 800 °C show that Bi-2212 grows rapidly at the expense of Bi-2201. Upon lowering the temperature to 500 °C and changing the atmosphere to Ar, a rapid increase in the lattice parameters was observed. We attribute this change to the loss of oxygen from the Bi-2212 lattice. The final material exhibited a Tc of 94 K.