Properties and structure of (Tl_0.5Pb_0.5)Sr₂(Ca_1−xNd_x)Cu₂O_z(Tl-1212) superconductors

Bulk material of Nd-doped Tl-1212 superconductors was prepared via a two-step procedure based on a wet chemical method to prepare precursor material followed by heat-treatment at 895 degrees C for 10 h. The samples with Nd stoichiometry of x = 0.05, 0.1, 0.15, 0.20 0.25 and 0.30 were characterized by XRD, electron microscopy and by resistance measurements. Oxygen stoichiometry of the specimens was analyzed. Lattice parameters were derived from x-ray diffraction and neutron diffraction measurements. The increase of the a-axis and the decrease of the c-axis as a function of the Nd content are discussed.