Abstract
We prepared Bi2Sr2CaCu2Oy polycrystalline superconductor by partially melting method in HNO3 or solid state method and investigated the influence of precursor condition and quench temperature upon the critical current density. The best starting temperatures of quench were 650°C in HNO3 method and 500°C in solid state method. In these conditions, critical current densities were 198A/cm2 in the former and 102A/cm2 in the latter. We found that starting temperature of quench influences the break of junctions between grains by thermal contraction and condition of precursor influences the occuring defect and grain growth in melting process.
It is important to select the best conditions of quench and precursor to prepare Bi2Sr2CaCu2Oy polycrystalline superconductor with high critical temperature and density by partially melting and quench method.
