Effects of Starting Materials and Preparation Conditions on Superconducting Properties of Ba2YCu3O7-δ Compounds

Three different types of CuO powders prepared by the neutralization method (CuO-I), the autoclave method (CuO-II) and the electrolysis method (CuO-III) were used to study the effect of starting materials on the superconducting properties of Ba2YCu3O7-δ compounds. T'cs measured by the electrical method are almost the same among the Ba2YCu3O7-δ compounds prepared from these CuO powders; however, J c and T c as measured by ac susceptibility were quite different. The J c value for the samples prepared using CuO-II was higher than that for the samples prepared using CuO-I and CuO-III. Optimum formation conditions to obtain the high J c samples were also investigated.