1 Department of Energy Conversion and Storage, Technical University of Denmark2 Electrofunctional materials, Department of Energy Conversion and Storage, Technical University of Denmark3 Department of Physics, Technical University of Denmark4 Neutrons and X-rays for Materials Physics, Department of Physics, Technical University of Denmark
Bulk polycrystalline samples with Bi1.72Pb0.34Sr1.87Ca1.91Cu3.13O9.83−x F x (0.00≤x≤0.51) were prepared by a solid-state route using CuF2 as a fluorine source. CuF2 was introduced in the precursor powders either by direct mixing with the other starting reagents or by addition to precalcined precursors. In both cases, CuF2 resulted in a clear lowering of the reaction temperature. The superconducting and secondary phase grains are larger in the CuF2 doped samples but the critical transition temperature and the lattice parameters of the high T c phase are not affected. EDS analysis shows that the fluorine is concentrated in SrF2 particles.
Journal of Superconductivity and Novel Magnetism, 2013, Vol 26, Issue 10, p. 3049-3056