OXYGEN STOICHIOMETRY, CRITICAL-TEMPERATURE AND PINNING MECHANISMS IN THE 2212 BSCCO SUPERCONDUCTOR

Accurate chemical and structural characterizations, critical temperatures (T(c)) derived from magnetic measurements and magnetization analysis of the pinning force density (F(p)) on a series of BSCCO samples have been used to model the effect of the oxygen content (y). The variations of c-axis, T(c)(y) and F(p)(y) are related to those of the irreversibility fields (B(irr)) through the change in the number of oxygen vacancies, which are considered as effective pinning sites. The scaling of F(p)(B) using B(irr) is analyzed.