TEMPERATURE-DEPENDENCE OF THE LOW-FIELD MAGNETIZATION OF GRANULAR SUPERCONDUCTORS

Calculations of low-field magnetization curves of superconducting gran ular systems an carried out by means of a critical-state model that fo llows from the Josephson-junction network description of this class of superconductors. An approximate analytical expression of the temperat ure-dependent effective critical current density J(c) is derived. Gene ral critical-state calculations which explicitly take account of tempe rature effects are thus specified to the case of a cylindrically symme tric polycrystalline superconducting sample. The calculated low-field magnetic properties are seen to be in good agreement with experimental results.