Analysis of the magnetic field distribution and estimation of the critical current density based on a magnetooptical study of the superconducting strip composites

The results of magnetic flux penetration into high-temperature superconducting composites of the second generation have been analyzed and described. The distribution of magnetic flux was observed experimentally using the magnetooptical visualization technique at various temperatures of 4.2–80 K. The experimental data have been found to coincide with the results of analytical and semi-numeric calculations of magnetic field profiles carried out for regimes of full and partial field penetration into superconducting composites. The method of estimating the critical current density based on measurements of the topography of the transverse magnetic flux has been considered, and an approach to estimating the critical current density for strips from measurements of the tangential field component has been proposed.