Critical current density and pinning mechanism in Hetero structure of Bi-2212 and MgB₂ superconductors

The systematic studies on hetero structure of Bi-2212 glass ceramic and MgB₂ superconductors are reported. Bulk multilayer superconductors were prepared with varying thickness of MgB₂ layer. X-ray diffraction and dc magnetization studies confirm the presence of both superconducting phases in hetero structured samples. Critical current density is found to be maximum in bilayer sample of Bi-2212 and MgB₂ superconductors. In tri-layer sample inverted anisotropy in J_c is observed because of multilayer growth process. The J_c at high magnetic field is attributed to different pinning mechanisms.