Modification of the trapped intragranular flux model for study of low-magnetic-field J(c)(B-a) dependence

We present a theoretical study of the influence of the intergranular flux t rapped in the J(c)(B-a) dependence for relatively low values of the externa l magnetic induction, B-a (B-a < 50 mT); taken into account that the cerami c behaves as a series-parallel array of Josephson junctions with Fraunhoffe r behavior. Also, we use the Kim and Bean critical state models to calculat e the inter- and intragranular magnetization respectively. When we introduc ed the intergranular magnetization the new model shows a good agreement wit h the experimental results in the system Bi-Sr-Ca-CuO that consists in the no-displacement of the maximum of the return curves to positive values of B -a.