Magnetic and Mössbauer studies of the superconductor Eu(Dy, Gd)Ba 2 Cu 3 O 7−δ

The changes of the microstructures of bulk single-phase Eu1−xDy x Ba2Cu3O7−δ and Eu1−yGd y Ba2Cu3O7−δ superconductors due to (Dy, Gd)-doping were investigated by the Mössbauer effect. The pinning potentials of the samples were calculated by magnetization relaxation analysis. The interaction between the magnetic moment of magnetic rare-earth cations and flux lines in these samples was considered as a predominant pinning mechanism in highTc superconductors in this paper.