Post annealing effects on 2223 phase of the Bi1.7 Pb0.3 Sr2 Ca2 Cu3 Oy system observed by microwave absorption

Samples having the starting stoichiometry of Bi1.7 Pb0.3 Sr2 Ca2 Cu3 Oy prepared from a mixture of Bi2 O3, Pb O and Sr2 Ca2 Cu3 O7 precursor have been investigated by magnetically modulated microwave absorption. The measurements clearly showed the presence of the 2223 phase in almost all of the distinct states in the same sample, although the resistance measurements exhibited single superconducting transitions. By short time annealing treatments in flowing nitrogen or oxygen atmosphere one may either develop one of the states or eliminate to a great extent the differences between states of 2223 phase. (author) 2 figs., 2 tabs., 8 refs