MAGNETICALLY MEASURED IRREVERSIBILITY TEMPERATURES IN SUPERCONDUCTING OXIDES AND ALLOYS

Irreversibility temperatures T(r)(H) were magnetically measured for the aligned powders of superconducting oxides, La1.85Sr0.15CuO4, YBa2Cu3O7, Bi2Sr2CaCu2O8, and Bi2Sr2Ca2Cu3O10, and for the metallic superconductors, Nb, Nb-Ti, Nb3Sn and PbMo6S8. the results are briefly discussed in terms of the thermally activated flux creep and the lattice or the glass melting models for the irreversibility temperatures. Also, the measurement procedures for T(r)(H) using a SQUID magnetometer are described in detail, since the measuring methods and the criteria which are used for T(r)(H) are important in the determination and interpretation of the temperatures.