Disclosure of hidden magnetic moments in low and high Tc hysteretic and semi-reversible type II superconductors during warming to Tc

摘要: We report on measurements of the evolution magnetization M upon warming from T 0 (4.2 or 77 K) to Tc for type II superconductors with locus initially situated along bridges between envelopes major hysteresis curves. Strongly hysteretic and semi-reversible specimens low high have been studied (Nb3 Zr, VTi, YBCO, Nb BiSCCO). Concentric, oppositely directed magnetic moments coexist in when lies bridges. focused cases where = 0, hence, before warming, constituent cancel each other exactly. Since they diminish magnitude at different rates as is increased Tc, their sequential `release' leads a rich variety phenomena. A simple model exploiting critical state, an equilibrium Meissner current conservation flux accounts all intricate behaviour encountered.