Characteristics of Bi(Pb)SrCaCuO superconducting ceramics samples properties by method of dynamic magnetic susceptibility measurements
Literature and experimental data about practical determination of phase composition and structure of BiHTSC ceramics from results of measurements of temperature dependence of magnetic susceptibility are presented. It is shown that Bi2223 to Bi2212 phases ratio, calculated by XRD-analysis results, does not correlate precisely with magnetic susceptibility - temperature dependence. Phase, which is present in smaller amount, especially Bi2212 phase with lower critical temperature, appears less pronouncedly at the magnetic susceptibility - temperature dependence. Besides, limiting parts of Meissner effect manifestation are peculiarities of contacts of superconducting grains. Different kinds of such contacts lead to lowering the critical temperature together with conservation of narrow transition interval, to division of transition into stages, and to increasing of transition interval. Among negative consequences of this influence there are hindrances in realization of grain oriented Bi ceramics synthesis scheme which imply powdering of samples consisting of chaotically evolved grains of Bi2223 phase, ordered placement of obtained plate grains of this phase - for example, through vibration compacting, and sintering.